Tech Tips

Tech Tips

If you have a ( general ) problem or if you like to get a partnumber than please check first the more than 1200 pages thick SZ workshopmanual, the RZ supplement, the SZ partsbook, the body repair video, or the service manuals please. Copies available.


The solutions / fixes etc. as explained over here are intended as a supplement to the workshop manuals and other known sources.
It is also not the case that all of these mentioned problems etc. occur at each SZ or RZ, but it is a collection of solutions / problems / advises built up over the years. Some problems occured in only a few cars worldwide.

1.) Tyres.
2.) Windscreen wipers.
3.) Brakes.
4.) Paint.
5.) Noises at the rear ( front ).
6.) RZ rust problem.
7.) Starting problem.
8.) Chip ecc. removal / replacement / codes / alternative.
9.) Airco.
10.) Antenna / Radio / Navigationsystem / Speakers / CD changer.
11.) Headlamps ( fogged up glasses / change to UK or back ecc. ).
12.) Cooling problems and location of the radiator bottle.
13.) Clutch.
14.) Mixture.
15.) Interior Switches.
16.) Steering Rack ( fuzzy feeling ).
17.) Rear window heating SZ.
18.) Insulating material under the SZ / RZ hood.
19.) Mudguards and wings over the frontwheels.
20.) Window wiper motor.

1a.) Tyres ( please check out the update from June 2017 below ).

You can use the Pirelli P-Zero NERO tyres in stead off the originally used P-Zero Asymetrico's. ( not ? for sale anymore for the SZ/RZ, but some alternatives have been tested past year. Please send me an email if you like to know more about it. ).
Sadly the P-7000 is not longer available,.. it was a very good alternative for the Asymetrico's and they did last much longer. After having contacts with some engeneers from Pirelli in the Netherlands and in Germany ( they did know about the SZ and RZ !! ) I got an excellent advise,.. The P-Zero Nero's would be the best alternative. We testet them in several weather ecc. ecc. conditions and indeed they are SUPER on the SZ and RZ !!

Not a good idear to take the Asymetrico's Pirelli also / still has in its production line ( they sometimes are offered as an alternative for the Nero's ), they have the same profile as the old Asymetrico's, wich had been specially produced for the SZ ( and F-40 ) in those days BUT the ones they now sell do NOT have the ( kevlar ) reinforced side walls as ment to be for the SZ / RZ. Those Asym's have been produced under a Porsche homologation. We tested them in the past on the track but they did not have the grip during cornering as the Asymetrico's or Nero's with reinforced walls have.

Also totally a "NO NO" is the: Pirelli SYSTEM wich means: Pirelli P ZERO Asymetrico at the rear side and P ZERO Direzionale at the front, that is on the SZ / RZ a worthless combination. Even years ago Pirelli ingeneers ( knowing the SZ very well ) in Germany, Italy and NL agreed with me about that. It is a kind of comfort combination, not really the thing for an SZ / RZ.

And so the originally used P-Zero-Asymetrico's could look like after a good afternoon at the track,... or after 8.000 - 10.000 km. normal street use,.... if they where bought NEW !!!!


Sometimes a new owner tells me proudly: "Wow,..... I found an SZ with only 3000 km's on the clock and even the tyres are still with 8 mm. profile and looking like new". It is tempting to keep them on the car than, but most wrecked SZ / RZ's I know of have been damaged by an accident caused by old tyres. Certainly in rainy conditions the SZ / RZ will be a "driving coffin" than !!

Be WARNED,..... !!!!! the original more than 15 years old P-Zero-Asymetrico's can look like those on the pics. even after a few months normal street use, they can explode spontaneously and often the inside of those tyres is rotten to upto the metal harnas !!!! Alfa Romeo did send in those days a special bulletin to the dealers to change after at the most 5 years those tyres and also that it is NOT allowed to repair them with a rubber plug ecc. Those tyres are life threatening certainly in the wet !!! Trow them away or your car will end on the scrapyard as most SZ / RZ's wich such old tyres before !!!!

Also an other WARNING is in place,.... NEVER EVER !!! replace the original metal valves in the wheels by normal rubber ones !!!! They can pop out spontaniously when driving the car hard ( circuit ) or under very hot weather circumstances


More about the tyres.

So the Pirelli P-Zero Nero tyre is hard / not to get at the moment. Registermembers have been experimenting with some alternatives past 3 years.
Those alternatives have been tested in several countries and some continents around the world by first owners of the SZ / RZ who drove with some types of tyres over the years as for instance the Pirelli a-symetrico, P7000 or the Nero's. They have been used in several road, track, hill and weather situation. Also several new members put them on their cars.

*** Liked till now are the Toyo Proxes T1R ZR 16 92W. They have also reinforced side walls and can handle the G-forces very well. They are not too expensive and do it amazingly well on the SZ / RZ.


*** Also tested are the: Bridgestone Potenza Re050A. They do not have the visible reinforced side walls.
These tyres are fitted as original equipment on the most powerful sports cars in the world like the Ferrari Enzo. They are also available in the aftermarket and are intended for sporty, demanding owners of powerful cars, luxury cars and sports models.


The positive comments ( not one negative reaction ! ) on those tyres are numerous, some mentioned down below:

Belgium comment on the Potenza's.

Ciao Eduard,

Hier een kleine uiteenzetting van mijn bevindingen met de Bridgestone potenza RE050 na de road trip door Italië. Ik mag dan wel geen testrijder zijn, ik heb toch wel op wat zaken gelet, die van pas kunnen komen om m'n bevindingen neer te pennen.

Algemeen zeer tevreden over de prestaties. Zowel op droog als nat wegdek vele kilometers gereden. Op nat wegdek altijd rustig aan gedaan, en dus nooit in de problemen geraakt. Op droog wegdek heb ik enkel de achteras weten uitbreken in haarspeldbochten.
De vooras geeft geen krimp. Bij het uitkomen van enkele bochten ging ik al eens wat eerder op het gas, en dat ging steeds zonder problemen, waarmee de SZ nog maar eens aantoonde prima wegliggingscapaciteiten te hebben! Nooit het gevoel gekregen dat de banden me in de problemen zouden brengen, in tegendeel! Deze banden geven vertrouwen! Deze banden zijn volgens mij een prima 'match' met het onderstel van de SZ. Mogelijk de beste straatband voor de SZ als je enkel naar prestaties kijkt. Zowel in de bergen als op de autobahn, droog of nat weer, de RE050s deden het wat mij betreft prima. De Passo Rombo, 'Trento Bondone'-hill climb, de Fernpass,... het ging allemaal best !

English comment:

Hi Ed,
I had and used original pirellis p zero 16 years ago for a few years. When I couldn't get them anymore I went to Bridgestone Potenza S01 which was a revelation much better ride and wet handling capabilities, but soft compound and wore quickly
Then the S01s ended production so I went SO2s harder compound better wearing with all the benefits of SO1.
Now the SO2 is no longer available I use the RE050 and they still retail all the benefits. I would recommend this tyre ! Kind regards.

German comment:

Hallo Ed,
Es freut mich von Dir zu hören. Ich hoffe heute kann ich Dir auch mal helfen.
Letztes Jahr hatte ich bei meinem SZ auch das Problem mit den Reifen. Ich habe mich dann für den Bridgestone Potenza Re050A entschieden.
Ein paar Wochen nach der Montage war ich in Italien. Auf dem Hinweg bin ich in extremen Regen gekommen. Ich hatte keinerlei Aquaplaning. Obwohl ich fast nichts mehr gesehen habe konnte ich noch 120km/h fahren.
Danach war ich bei Super Wetter in Francia Corta auf der Rennstrecke. Ich bin dort insgesamt eineinhalb Stunden Vollgas gefahren. Auch dort hat der Reifen bestens gehalten.
Natürlich kann man den Reifen auf der Rennstrecke an seine Grenzen bringen, aber die liegt ziemlich weit oben.
Meiner Meinung nach ist der Reifen für den SZ bestens geeignet und er passt auch von der Optik sehr gut zu dem Auto.
Anbei zwei Bilder die ich nach einem Stint gemacht habe. Bis auf den Pickup sieht man sehr schön wie die Reifen Gripp aufgebaut haben.



*** >>> Update Juny 2017: <<<

Both the Toyo Proxes and the Bridgestone Potenza's are difficult or not to get anymore in the sizes needed for the SZ / RZ. So some alternatives have been tested.

One of them is the Bridgestone RE 002 Adrenalin. It has been tested ( In dry and wet ) by some very experienced SZ / RZ drivers on track and at high speeds on highways whithout speed limits in Germany etc.

Those test-drivers also had experiences with the Pirelli before and they think the Bridgstones are superior at the moment.




If you also have / put the Bridgestone RE 002 Adrenalin on your SZ / RZ, than please let me know your experiences with this tyre.

1b.) The Spare wheel tyre.

The tyre's dimension is: 115 x 85 R18 96 M produced by Michelin


I personally always took some tyre repair spray cans goop with me in the boot, plus a tyre repair kit and a little 12 v.compressor. That would still be the best option, because that old ( 1990 ) emergency wheel tyre can not be trusted anymore to be safe.

If it would be neccesary for M.O.T. or other reasons to have a new spare tyre, than there is a problem, because Michelin and others do not produce tyres in those sizes anymore.

One of our registermembers found in 2018 the right replacement, and maybe a good idear to replace the old Michelin for a new tyre, now they are still available from Pirelli, but how long ??? ( as far as I know at this moment the only company which still produce it the the right size and load weight ).


Pirelli Tyres / Temp Space Saver / Pirelli Spare - 115/85 R18 T 96M TL


2.) Windscreen wipers.

For me the original wipers where not long enough, also they did not do their job very good, so I tried several things on my first SZ and after some experiments I came up with the following solution and that worked well, also for many other SZ drivers all over the world who changed the wipers also.

In stead of the original windscreen wipers you can use the Bosch 480 S wipers - Bosch part number: 3397118541 ( In the UK called 19S ). They are 3 centimeters longer, so taller persons will have a better view. Also the left wiper does have a little spoiler that prevents "lifting" at higher speeds.

Bosch 480 S wipers

3.) Brakes.

a.) The front "Alfa Romeo SZ / RZ" brake discs you could also buy from Brembo's,..but also not available anymore, the Brembo id. number was: 09.4984.10 . Also there were disks from Breco ( exact the same as Brembo, made by Brembo at the same productionlines as the Brembo's.. but sold via other channels, under the name BRECO ) id. number front disks: BS 8023 - 60552375, rear disks: BS 8024 - 60552111, but also not available anymore. Sometimes traders offer old stock and there are also some "after sales" possibilities.

b.) The 23 mm. Master brake cylinder for the SZ / RZ is no where for sale anymore,... I still have a few repairkits in stock, but if you do not have bigger brakes on the SZ, you can also use the 22 mm. from the 75. If you use 6 pots brake calipers than it is even better to take a 25 mm. master brake cylinder as the flued displacement is better.

c.) The brake compensator ( brake force distributor sitting next to the master cylinder ) often causes problems on cars that where stored for a long time. You can carefully open it and repair it. ( officially not allowed, so be very careful and do not attempt if not acquainted with brake systems ) those items are not for sale also anymore and the ones from the 75's etc. have a different part number, they do fit,.. but probably divide the braking power in a different way.


d.) Also the vacuum valve, placed on the inlet manifold can cause problems. Often because the cars have not been used for a long time the valve sticks, your brake booster will not give much / non assistance anymore. Replacing or cleaning the valve is a good idear to start with if the brake feel is not very good it only cost a few euro and still available. On later series of the Alfa Romeo 75 ecc. this valve has been replaced by a seperate valve that is mounted in between the hose going to the brake booster.


e.) We tested a modification of the brakes wich has been tried by a few SZ drivers now ( including myself ).
Some comments from SZ drivers who tried / tested this modification:
*.) WOW !!!! For about 10,00 euro I can now lock all the 4 wheels while braking. Also tested on the track, a BIG improvement, even using cheap aftermarket brake pads !
*.) Concerning, the brakes: I think it is an improvement although there is still difference with respect to the braking of modern Alfa cars. This morning I had another drive with the SZ to test the brakes, in my opinion it is a consistent improvement.
*.)I can notice a much better brake after I have rev. up the engine and I go braking just after, this is the case that you drive relatively fast, it is easy to block the front wheels but the control is very good.
If you just take the car and run with the engine below 2000 rpm and then you brake, it feels like before the mod.
I assume that the new valve is capable to work with higher depression, building it when releasing the trottle at high rpm. Soo...good mod. in my opinion.
*.) Just getting rid of the smell of burning brake pads in my nose myself, after my first testrun with this modification in my personal car, I can only confirm what the former SZ driver also stated. It feels better, harder pedal and if it is pressed hard at high speeds there is happening much more than before. But indeed,... braking will never be as light as it is in modern cars. For this money and 15 minutes of work a BIG improvement, but it will never be as good as 4 pots Brembo's or AP's of course.

Than now how / what has been done:


After having had many problems with the metal vacuum valve placed on the inlet manifold, Alfa Romeo decided on later cars to replace it by a plastic one, mounted in between the hose going to the brake booster. The valves with the part numbers: 60501691 ( used on the 164, 75 and 33 ) or 60543892 ( used on the 75 and 33 ) where used in stead of the metal one.
We made a modification with the plastic valve also on an SZ, and to our surprise the feeling in the pedal and the assistance while braking improved also.

How to make the mod: ( see pictures )

If you want to see a larger picture, click the thumbnail .

valve valve valve valve valve

Take off the metall valve,... drill a hole trough that valve. Be sure that every metal part from the valve has been drilled out and clean the inside from the metal casing very carefully. Than put it back on place, cut the original hose in half and place the plastic valve in between... !!! ATTENTION !!!!,... there is an arrow on the plastic valve and that arrow has to point into the direction of the engine ( old modified valve ) because it only works in one way. Put two extra clamps over the hose in front and behind the valve.
Start the engine,..let it run a few minutes,... press and release the trottle and the brakes while standing,.. than carefully make your first testdrive.
If all went fine, than try an emergency brake and you will notice that you still have to press the pedal with some force as before, but that the brakes will react more agressive.
If you want to be sure that you can go back to the old situation as before the mod. it would be wise to buy a new metal valve and a special hose together with the new plastic valve. Than you can drill-out the old metal valve,.. use the new hose and keep the original parts aside.

!!!! WARNING !!!!

Inspite of the fact that Alfa Romeo also made this modification on later cars, and the fact that we tested it on a few SZ's, even on the track ecc. it will be always your OWN responsibility if you alter things.
If you decide to give the mod a try,.. than please let me know how you like it:

f.) If you are taking the car on a track it is best to have a heat protection cover around the brake master cylinder etc. and to use high quality racing braking flued, like ATE Blue Racing for instance. Also a good idear is it to remove the litts mounted at the front mudguards ( wich allow access to the indicators, or to remove the complete mud guards ) wich allows cool air from the frontbumper air intakes to reach the brakes. It is also possible to duct air to the left and right side callipers from the frontbumper, trough hoses coming from the left and right side from the front bumper, trough those holes in the mudguards.

extra air

g.) Several race drivers all over the world also have as hobby car an SZ / RZ in their collection, and they take it onto the tracks also. Often they drive up front even with the original brakes ( Brembo ),.... Most people do not like the original brakes due to the poor "feel", but according to most racing drivers the brakes are not at all bad.

h.) If you like to upgrade your brakes and have checked the above suggestions, than is our experience after testing a LOT of stuff that in the orginal calipers the pads from "HAWK" ( HP+ HB 180 ) are very good for street and track. Other brands of pads are maybe good on the track,.. but it is advisable to change them if using the car normally, because they often perform poorly when the brakes are cold.
Update in 2016: One of our members tested the brakes on his SZ during a Mille Miglia tour in Italy with he above mentioned mods. He used the next pads and they where more than perfect upto the job when cold and warm / hot. Ferrodo 2500 DS, at the frontside: FCP565H and at the rear: FCP596H.

i.) Brake calipers... we have tried several possibilities, ( also the Tarox 6 pots set, but not satisfactory at all, certainly not on the track ).

The most satisfying till now are the 4 pots calipers from AP, with bigger, grooved and drilled discs and special metal reinforced hoses. ( see tuning section of the page ). AP 4 pots brakes where also used on the former trophy racers ( some even used the standard brakes ) and several SZ / RZ owners all over the world have also mounted them allready. They fit in the original wheels.

AP set

Also the Alfa Romeo GTA calipers ecc. as shown under the "Tuning" topic seems do to their job very good. Only problem is that they probably do not fit in the original 16 inch wheels.

We did not test the 4 pots brembo mod.... yet. but I am interested in the experiences from drivers who have them on their SZ/RZ.

j.) Rear brake calipers... Not available via Alfa Romeo anymore since several years. Also for the 75 hard to find new ones, but there are companies selling re-newed Alfa Romeo 75 rear calipers. You can use those also. You have to take the spacers out of the original calipers and install them in the re-newed calipers.

rear brakes

It is also possible to get an new aftermarket spacer-set, but not neccesary if the old spacers are still in a good condition.


If you want to see a larger picture, click the thumbnail .

rear brakes rear brakes rear brakes rear brakes rear brakes rear brakes rear brakes rear brakes

k.) The rubber flexible brake lines to the callipers are after 20 years normally due to replacement. Replacing them by "metal-flex" brake lines will give also an improvement and a much "harder" pedal. In some countries those metal flex brake lines are forbidden.

flexible brake lines

4.) Paint / Blistering / colour codes.

A common problem that many SZ's and even RZ's have is blistering / micro blisters ( like rain drops ) under the paint. It was a production problem with the modar parts. The only solution is sanding the paint off completely, and than having a new layer of paint over the bare shell. It is no guarantee that the problem will not come back,..altough - if it does - it will be less than before. In the UK is one guy the "champion of blisters",..he has ones from more than 1 cm. big !! I never ever saw them in that size myself. If you have the car repainted, then do not risk to take out the windscreens, and be carefull taking out the rubber/plastic profiles,..... all are not available anymore.

If you want to see a larger picture, click the thumbnail .

blisters blisters blisters blisters blisters

The color of the SZ is Rosso Alfa 130 Duo Tone.
The color of the grey roof is according to an SZ owner - Mr. S. Schwittek - Grigio Scuro, made by PPG number 487533/1. Seems that the same colour was used on the front bumper and side skirts from the Alfa Romeo 164 QV.
Alfa Romeo's colour number seems to be Grigio Scuro AR 633.

The trick is to make the transparant top layer as less shiny as possible ( 50% transparent paint and 50% stuff to make this transparent paint less glossy,.. the paintshop will know what to do,.... I hope ! )

One SZ was made in the color black, it was the personal car from Dr. Andrea Zagato. Also it seems that a few SZ's where painted yellow and sold to Japan.
The RZ was available is three colors, red, yellow ( PPG 258 Giallo Ginestra ) and black (PPG 601 Nero - two coats ). Three RZ's were made in the color silver and one in the color metallic white.

Silver RZ Silver RZ

5.) Noises at the rear.

The suspension of the SZ / RZ can make a sort of clicking, squeaking, and/or screaming noises.... very scaring for most owners !!

a.) Alfa Romeo did find a solution for this problem but never shared that with their dealers !
I got it after some years via some very serious contacts out of their secret companies database.

In my experience is that the solution they discribed will solve the problem in most cases.

They only forgot to produce the parts needed to solve that problem !

!! WE did !! These parts have been sent all over the world and registermembers gave it the name: "Anti Rattle Kit".

*** Do you like to get rid of those specific noises, than we have the parts and instructions needed to do so. Let me know ! ***

b.) If the "anti rattle kit" does not cure the problem, the noise may be caused by the uniballkit in the front of de-dion rear axle. Those kits are not available anymore since many years but I still have a few in stock. They contain the uniball-housing, the uniball itself, 2 spacers and a clip.

!!! Some traders sell similar kits for the Alfa Romeo 75, but in stead of an expensive unibolt they use a bearing. For the Alfa 75 not a problem, but for the SZ / RZ with is hight adjustment and changing angles of the rear suspension it is !!!

de dion kit

c.) Other possibilities are noises that come from the top of the springs,...spray a lot of teflon spray or alike on the top of the spings and pray that the noises will disapear.

d.) And another cause can be a hammering noise on the boot floor, wich is the metal collar from a hydraulic hose behind the spare wheel in the boot. The collar normally is mounted under a rubber clip,..but often that rubber insert slides away.

metal collar

e.) There can also be an other kind of noises, like the ones coming from bad rear wheel bearings / axle ends or differential.
Bad bearings often can be found at very low milage cars wich stood still for a long time. A bad differential almost never happens.

f.) Plus an other kind of noise,..sounding like "whiiiiii...." can be caused by a bad fuel pump.

*** Noises at the front side. This is a reasonably recent problem, first mentioned to me in 2012. Till now 2 cars had the same problem and has been cured simply. If you have noticed this also on your car, please let me know and I can give you some advise etc.***

6.) RZ rust problem.

This section is aimed at all drivers of the Alfa Romeo R.Z. Zagato. Since the body panels are made of Modar, a special kind of plastic, you would not expect this car to rust at any outside spot. In fact, there is one critical location that in most cases accommodates rust. The location in questions is the rabbet underneath the roof cover. Open the roof cover and carefully remove this gasket that you find on top of the rear fender. The reason for a possible rust nest there lies in a construction fault: First of all, water hardly is able to disappear from this place. Consequently the water moves underneath the gasket where it gets into contact with the rabbet. In addition to that the rear carpet is not only fixed with screws but also with adhesive tape that sticks under the gasket onto the rabbet.

RZ rust

Therefore the water does not only stay underneath the gasket but also under the tape -after a couple of years the chemical reaction will create rust. If this location is checked in treated in time, further damage can be avoided Since there is only limited space around this rabbet, it is very difficult and time consuming to get rid of the rust. The best thing to do is to use a screwdriver and remove the rough rust as good as possible. Make sure that after this treatment no further rust remains in the gap between rabbet and fender. Then a rust converter should be used. Very good experience was gained with "Fertan". It is an easy to use, non aggressive rust converter, which should be applied with a brush. Let it work over night or even better for 48 hours and the rabbet is absolutely rust free. It is now ready for a layer of paint underneath the outermost layer. Make sure that before fixing the gasket all rests of rust sticking on there are eliminated.

RZ rust

Now your R.Z. is protected for many years at this dangerous, potential rust spot.

7.) Starting problem SZ / RZ ---- more often with warm engine

a.) First thing of course is to check the condition of the battery ( also check out techtip 52: Overheating or exploding battery !!! ).

b.) Second thing is to check if the wire to the starter motor did not work itself loose, making bad or no contact anymore.

starting problem

At some cars it even is possible that the wire that connects the ignition key to the starter has been badly attached to the starter.
In that case it is possible that the screw had loosened, so it will sometimes make good contact, and sometimes bad contact.
An easy fix: replace the screw with a new one, to which best be added one or two grover and dented washers in order to prevent the screw from loosening up again in the future.

starting problem

c.) Only start the engine with turned off big users as the airconditioner, rear window heating or headlamps.

d.) Also check problems that could possibly arise from the installation of an alarm system or immobilizer. A bad battery in the transmitter / r.c. of an alarm can also cause starting problems. Often a reset from the system and new battery can cure those issues.

e.) After turning the key, sometimes nothing happens, often even no click ! Than after waiting for some time, turning off big users like the airco etc. and a next try it may start, but often several "tries" or waiting for some time with a opened bonnet are neccesary ! Several SZ / RZ's do have this problem.
It has also been noticed that SZ's or RZ's with only a few miles on the clock have similar issues.

An other problem is that after the years also the starter is even a bit more critical, asks for a bit more power to turn the engine.

I resolved the hot starting problem at my SZ completely ( plus is has been done at several SZ / RZ's now over the years ).

I can start with any battery old or new, even with the airconditioning and all the other users on, cold engine, warm engine all not a problem anymore and the best thing, it is an easy job to do in the way we found out, but it took many hours and energy to find a perfect, almost invisible solution.

No thick leads from the battery crossing the enginebay or what ever, no cutting wires, no "over-powering" existing wires but by cleverly using excisting hidden sockets etc. we could solve the problem without the possibility that the cable tree, fuse box or what ever is melting down !

The most important thing is that there has not been tampered around with the original wiring !!! Everything must be as supplied by Alfa Romeo in their original condition in order to avoid new problems that could occur, possibly because of the modification that has been made. Our fix for the problem as been proven many times over the years. The modification is 100% effective for SZ / RZ's which still have all the original wiring

*** If you have been granted full access to the hidden part of the site you can ask me for more information or pictures. ***

f.) It is also possible that the relais from the injection system are defect ( but than the starter will run, after turning the ignition key ) . They are located if you look under the bonnet at the outer left side of the engine bay. Probably not for sale via Alfa Romeo anymore,..but the Bosch numbers are for the outer left one: 0332014112 and for the right side one: 0332014113.

starting problem

g.) Kindly Jamie Porter also gave the next extra info on the "hot starting" topic. The starter motor is running in this case, but engine does not start.

starting problem

Jamie Porter: With regard to hot starting it is also necessary to check the fuel holding pressure in the system as if it falls off to quickly the car will take ages to hot start.

h.) The engine stops / dies at speed and refuse to restart until cold.

This problem can be caused by corrosion on the coolant temperature sensor connections which creates a high resistance causing the ECU to interpret this as no need for fuel, and the engine would die and only restart when the engine got cold (the resistance would fall).

8.) Chip.

a.) The computer is under the carpet at the passenger side. Many SZ / RZ drivers are looking to get more power. Squadra Tuning a specialized company in The Netherlands is offering an alternative chip. It is installed allready in many SZ / RZ's all over the world and till now I never have heard of any problems.

If you want to see a larger picture, click the thumbnail .

ecu ecu ecu ecu ecu ecu ecu ecu ecu ecu ecu ecu ecu ecu ecu ecu

b.) Codes / Alternatives ecc.

A lot of "interesting" stuff is written on forums etc.... but this seems to be the whole story,.....
For the SZ / RZ is used the Bosch Motronic computer code 4.1
ECU code is: Bosch: 0261200141
Chip used is: DIL 2827 C 256


Alternative: The Alfa Romeo 75 V6 QV, it has the same motronic but it has other software on the chip:
Software version for the 75 QV V6 is 126735737.
BUT !!!!! :
Some 75's QV V6 had the same software as the SZ / RZ and that has software code: 1267356097.

chip SZ RZ

I was lucky to buy some time ago a 75 V6 QV computer with the SZ / RZ chip ( software ) on it.
But if you are un-lucky with the chip, you can always decide to put a "SQUADRA" chip as replacement in that computer.
I personally even am convinced that Alfa Romeo experimented with chip settings and cam shafts during the production. I drove several SZ/RZ's from first - middle and end series and I noticed some differences in top speeds / idling / torque / and the rev restrictor coming in,....
At some SZ/RZ's the rev restrictor is coming in at 6.300 revs, others at 6.500 or 6.800, but also at some SZ's it comes in over 7000 revs.

An Australian "investigator" from the motronic ML4.1 software etc. shared the following info with me:


An SZ running the "BF43" chip (s/w code 1267356097) actually has two rev limiters (not counting the possible rotor button limiter that you've also mentioned).
There's a "soft" limiter which can be exceeded for a pre-set amount of time before it cuts in, and there's a "hard" limiter that is the absolute limit that the ECU will allow.
The QV version of the chip for this ECU (1267355737 / 9AE3) has the soft limiter at 6080 rpm and a soft limiter timer of 1.5 seconds. The hard limiter is 6592 rpm. This means that the QV can exceed 6080 rpm for a maximum of 1.5 seconds before the rev limiter kicks in, but if 6592 rpm is reached within that 1.5s then the hard limiter kicks in immediately.
But the SZ (BF43) has the soft limiter set to 6520 rpm, i.e. just a tiny bit below the hard limiter, so the hard limiter would be hit almost immediately as it's only 72 rpm higher. The 6300-6800 rpm that you noted for rev limiter activation is likely to be tachometer inaccuracy rather than a difference in ECU settings, +/-250 rpm is pretty normal for tachos of that era.


In the 7xx series of SZ's several SZ's are idling very unregulary, but they have high top speeds ( 275 km/h and they stop there on the rev. districtor, but even than it feels that they can go on and on !! ).... at other SZ's ( first series ) till 3000 revs is happening not too much,.. but keeping the footh on the trottle makes the car launch after that 3000 revs, and also in the first series there are cars that can reach 275 km/h. without any problems.
Other SZ's have a more regular curve and power is coming in from down under regulary.
The Tropy racers also had another chip, but I think also in some "normal" SZ's they put that chip ???

c.) Alternative ECU. ( hidden part of the site )

d.) More diagnostic info needed,....:
At the footh end at the passenger side under the dash there are 3 connectors:
* One connector with 2 poles ( red connector )... you can see if it has the QV or SZ software.
* A 3 poled connector: you can attach a diagnostic computer on it.
* A 4 poled connector: a diagnostic blinking code connector.

e.) If you are not the first owner of the car it might be a good idear to check the distributor rotor arm. The SZ / RZ has an electronicly arranged rev. restrictor, but older types of 75 etc. used a same type of rotor arm BUT with a mechanically rev-restrictor build in. Those restrictors can come in earlier as normal for the SZ / RZ. So IF the distributor rotor arm on your car has a mechanical restrictor, than you can better replace it by an un-restricted one.

9.) Air conditioning.


a.) In most countries it is not allowed to refill it with FREON ( R12 ) anymore, but is some countries it is still possible to use an alternative called: R 413 A. By using that alternative gas you do not have to rebuild the airconditioning system as the gas does not attack the seals and the drop in gas does not need a higher pressure system.
!! Since 2010 it is also possible to get R437A wich is a full replacement gas for R12 and even a better alternative than R413A wich can "fall apart" over a number of years. If that happens, than it does not lubricate the system sufficient enough anymore. Because of that reason it is good to have a system wich has been filled with R413A, checked / refilled every 2-3 years.
The cooling result with R413A is as good as with the original FREON. The cooling result with R437A is about 10% better !
The system contains 900 gr. ( 0,90 kg. ) Freon or alternative.

**** BUT,...if you use R437a then only fill 85% of that 900 gram because the density is different from R12 and R413a.****


b.) On the first series SZ's the airconditioning tubes ran into the console above the passengers feet. In certain circumstances condensation is formed on those tubes. This condensation will form black drops on the anti-condensation material around the tubes. These drops can make black stains into the carpets. Solution,.... BUY black carpets,... hahahaha !!

c.) It happens that the drainage water of the air conditioning overflows in the car, behind the console.
Probably the drain hose is then blocked somewhere, or the lips of the end of the hose under the car are stuck to each other. Check the end, separate the lips from each other and cut a V-tip in the end, so that drain water can always go through.


If that does not do the job, than:

Remove the left side panel from the console.
The drain is a ribbed hose attached to the air conditioning unit.


Remove the hose and check that there is no kink in the drain.


Then move with a long wire through the ribbed hose until it comes out under the car.


Rinse the hose thoroughly from above with water or compressed air.

Also see techtip number 23e.

d.) Another problem wich causing the airco not functioning well is a bad pressure valve. It is located under the dash at the passenger side. The airco is making hissing noises and does not cool very well.

e.) BUT,..that valve also can produce noises if the pressure in the system is not high enough anymore, because a lack of enough gas. The molecules from the refrigerant are so small that 10% escapes through the rubber tubing every year. So it is a good idear to have every 3-5 years the system refilled and checked out.

f.) It is also possible to add some stuff to the gas, that will give visible staines - when leaking somewhere - by shining with an ultraviolet lamp on possible places where leakage could appear.

pressure valve airco

This part is not available anymore via Alfa Romeo,..but the ones from certain Renaults will fit. Only the connection has to be modified a bit.

f.) Upgrading the airco to R134A gas / Replacing the original compressor for an alternative one.


If your SZ / RZ airco compressor pump ( built for Freon / R12 ) is beyond repair or if you like to rebuild the airco system to operate on the nowadays used gas R134A than we found a perfect solution.

The R12 original SZ / RZ pump is no longer available, so if you need an alternative it seems best to have one also suitable to use with the modern gas R134A.

*** If you have been granted access to the hidden part of the site you can ask me for more information or pictures. ***

10.) Antenna / Radio / Navigationsystem / Speakers / CD changer.

a.) From most SZ / RZ's the antenna does cause problems, an alternative antenna is the black antenna from Hirschmann. HIT AUTA 5091 SW, number 921010-001. If you swap the Hirschmann outside trim with the original one from the SZ than you will see no difference.
b.) The audio-filter, mounted under the rearshelf where the speakers are can misfunction, often caused by corroded contacts. You can take away the rear shelf,..than disconnect the filter and clean the contacts. ( you can see the connector for the filter sitting under the shelf if you take a look from the boot to under the shelf ).
If there is a bad contact it sometimes helps when you give the shelf a little "slap" at the place where the filter is fitted.


c.) Radio: The SZ did not came with a radio,... the RZ with a Clarion audiocassette radio CRX111R,... if you like you could connect for instance a Clarion DC628 CD changer to it.
SZ: Behind the black coverbox in the DIN opening you normally can find an ISO connector.

d.) Speakers: it can be that at the original speakers the foam completely has disintegrated. So probably you like to replace those speakers by alternatives. Proper replacement sizes are: 4.00 inch and 8.00 inch



For reference you can see the depth is equivalent to the replacements Audison APX4 and AP8 which have dimensions online. Original grills fit over this brand speakers.



e.) A "built in" Navigation system or radio does aquire a "pulse signal" but the SZ or RZ does not have a special wire to get that pulse from the pulse generator. I found out that the easiest way to get that pulse is to split the grey wire ( at my cars is always was a grey wire ) from the connector at the rear side of the speedo,.... at the picuture the orange wire. Than bring that orange wire to the rear of the console. I myself always used a Becker Traffic Pro radio plus CD changer ( cd changer glued with high quality double sided tape on top of the right side from the patrol tank in the boot, some people put it under the passengerseat ), because it is high quality and looks good in the SZ.

pulse wire

11.) Headlamps.

a.) Removal and installation.


1.) Disconnect negative battery terminal.

2.) Disconnect connector of headlight to be replaced.

3.) PRESS HEADLIGHT FROM INSIDE OUTWARDS, OVERCOMING THE RESISTANCE OF THE 3 PRESSURE PINS, unscrew the metal frame and remove it, than you can take out the lamp in the direction of the engine.

!! Warning: only do this in a heated garage or warm circumstances, otherwise it is possible that the plastic clamps at the headlights will break , because cold plastic is harder and more fragile !!

4.) At the first 15 SZ's you obviously could push the headlamps trough the holes in the front bumper to remove them.


Solution from the 16th. SZ on: it is also necessary to take off the metal frame ( 1 ) around the back of the headlamp. Remove it by unscrewing the 2 screws ( 2 ).




5.) Reinstall, reversing removal procedure.


plastic things

b.) Problems with the headlamps.

If you need to clean the inside of the glasses when fogged up ( a common problem ) or to convert them to UK specs or the other way around you have to turn the deflectorplate around and take the lamp apart as shown below. The deflectorplate as shown is in the European position. UK position is the other way around.

If you want to see a larger picture, click the thumbnail .

lamp lamp lamp lamp lamp lamp lamp lamp lamp lamp lamp lamp

c.) It almost never ever happens that also the other headlamps have fogged up glasses, but if that is the case it is impossible to take off the glasses without braking them. So you have to be inventive with a piece of ironwire and some cotton wool as shown in the pics below. To take of the oily fog it is best to use spirit.

If you want to see a larger picture, click the thumbnail .

lamp lamp lamp lamp

d.) The SZ / RZ dipped head lamps give poor light, but better NOT to use those ultra bright / ultra white etc. bulbs in your lamps, because they can fry the reflectors or tan them brown and make them useless !!

e.) If you need to adjust the dipped headlamps, than first loosen the top bracket that keeps the lamp in place, otherwise it is almost impossible to adjust the lamps properly and you will probably brake / damage the plastic plugs where the adjusting screws are going trough. After adjusting you have to bend the bracket back on the right place carefully, without tension on that bracket. ( otherwise the lamp will change its position and has to be adjusted again ).


The little plastic parts - where the screws to adjust the lamps go trough - I stil have some in stock. Often they are broken and not for sale anymore.

plastic things

f.) How to remove a broken head lamp glass. *** If you have been granted access to the hidden part of the site you can ask me for more information or pictures. ***

12.) Cooling problems.

Obviously a good mechanic would check first if the thermostat on top of the pump is still functioning well, second thing would be checking if the fan comes in at the right temperature. If not, the fan sender / wiring / relais etc. have to be checked etc.
Problem with the thermostat is that the housing and thermostat have been built together and they are different from the ones used in the 75. The cooling flued exit opening is turned to the other side and because of that also the top radiator hose has a different form.


It is possible to use the 75 thermostat, but the top hose have to be altered accordingly. Also possible to use a 164 thermostat by taking it out of its housing by bending some metal lips etc. It can be swapped over to the original SZ/RZ thermostats housing by removing its inside in the same way. Temperature setting from a 164 thermostat is a little different than the one used for the SZ / RZ.

Strangely not all SZ / RZ's suffer from cooling problems under hot / hard circumstances, but some do and a good solution for every car with this problem is not always possible.
Some members solved the problem by using one of the fixes as explained below.

We experimented with an alternative waterpump with smaller pulley to make the water passing the radiator more quickly, but it did not lead to the desired result. Than we finished an other project with a positive outcome. It has been tested on an SZ with a a persistent cooling-problem used in hot conditions. The mod wich has been done gave the final solution ! Idling the car for a morning with outside temps from above 32 degrees and the aircon on, was possible since the mod had been done. The engines water temps did not exceed 92 degrees !

Some other possible solutions I have under the "hidden section of the site" as also more information about our "Coolkit" wich will solve the cooling problems even under extreme circumstances.

*** If you have been granted full access to the hidden part of the site you can ask me for more information or pictures. ***

a.) If your car has cooling problems in normal circumstances,..please check first if the electric cooling system is functioning correctely, the fan sender ( the terminals can corrode ), but also if the relay is still functioning and if the red + wires going to the little black +connection box on top of the fender is not loose or corroded. The cooling fan should switch on just over 90 degrees and then cycle on and off.

loose contacts

loose contacts

b.) The SZ / RZ's engines tend to run hot not because of the capacity of the cooling system but because of the fact that the heat can not go anywhere.... the engine bay is almost a closed box and there is almost no flow of air over the engine. SZ / RZ drivers did try various things to make it more open, such as taken away the polyester plate under the engine,... or opening the fake "louvres"

opened louvres

opened louvres

opened louvres

c.) Also some drivers had a special radiator been made with a higher capacity and / or a fan sender that comes in earlier ( 80-85 degrees ). The original ones are coming in at 92-95 degrees Celcius,.. but be aware the temp. gauge is not always accurate.

d.) Also a few register members have mounted an engine oil cooler to help keep things cooler.


e.) In summer traffic jams or on the circuit the engine can also overheat,..some people have mounted a remote switch under the dash to turn the fan on manually in these situations.

f.) If the igniton key is turned off there can be situations that the temperatures can rise too high, because of the fan is not able to work with the ignition off. To avoid this, you could make a little modification. Looking under the hood there are 2 relais sitting on the left side... one of them is for the electric fan ( sometimes they are swapped over, so you have to try it out wich one it is )...take the pink coloured wire ( sometimes other colours have been used ) out of the connector under the relay ( tape it off ) and make a new red + wire to the little black + connectorbox on top of the fender ( see pics ), be sure, a 15 amp. fuse in between that wire.

fan mod

fan mod

fan mod

fan mod

g.) Than I got the following tip from our Malaysian SZ driver Mr.Eu Ky Chan:
"I have a suggestion to contribute on cooling problems which I found works well in keeping my SZ #723 cool even in traffic jam (bear in mind Malaysia is in the tropics & daytime temperature is always >30 degrees celsius unless its raining), its called Redline Water Wetter. Have you tried it before? If not, please do give it a try."
I know that that product does exist,..but never tried it out myself,..but I certainly will do so next summer.

h.) From Stefano Borin - racing a modified 24 valve SZ - I got the following modification: to give the airintake more air and to keep things a bit cooler "behind the front bumper" he made the holes left and right from the radiator bigger. I personally think it does not disturb originality too much.

airintake mod

i.) Some people take really drastic measures to keep things cool,.... OEF !!

frond bumper mod.

And certainly a bi-turbo needs more air.

bonnet mod.

j.) An other alternative is to use a fan with a higher capacity. A registermember did experiment with a fan from the company Sandtler - Bochum - Germany. The capacity from that fan is 3250 m/h. It is bigger, quieter and covers almost the complete radiator surface. Further more it fits without problems and it is a simple "bolt on" job that everybody can do himself. The fan is also a good alternative for if the original fan has broken down. The original fan is not available anymore via Alfa Romeo. BUT in the end this solution also did not bring a complete cure against overheating.



k.) Electrical surprise !!

Totally unexpected an SZ driver found in 2013 another cause for "the cooling problem" on his car. He had a strange cooling problem, but to find the cause and the solution took about 2 years.

Occasionally and only at days with high temperatures a fuse was blown but without an obvious cause and it was often not immediately noticeable, because that fuse did not involve many other visible or neccesary functions during driving.

Over that same "fuse group" also the fan was functioning ( or not ). If that fuse was blown, obviously the fan stopped and the engine started overheating !

But, why did that fuse on that SZ blew ?

After intensive investigations on hot days the problem has been detected. It has been caused by the interior light at the ceiling.


Iron parts ( plus side ) could make on hot days just contact with the minus side ( inside metal roof frame ) of the car. Making the fuse blow or causing at least malfunctions.

That interior light is crap quality and also at one of my SZ's I had to change it for a new one, because it fell apart. Also at that car it made the fuse blew out, but I never made in my mind also a possible connection to the cooling problem.


!!! Be aware also if you need to change a bulb in that interior light. It is best to disconnect the battery first, because it is very easy to to touch the metal inner frame of the roof and to short circuit ( and to cause some fireworks ) the electric system !!!

l.) Even the bigger fan was still not enough in certain circumstances.
One of our last attempts was mounting another waterpump with a smaller pulley to make the coolant go around quicker trough the system. That was no succes.

m.) A Japanese member put some airducts into the polyester plate under the engine.


n.) !!!!! THE SOLUTION at last !!!!!

A register member living in the South of Europe did not gave up to find a fix for this persistent problem on his car and I think he found the best solution and that lead to the construction of a special "SZ / RZ COOLKIT" wich can be installed easlily on existing bolts etc.

*** If you have been granted full access to the hidden part of the site you can ask me for more information or pictures. ***

A totally different problem is the location of the Expansion tank / radiator bottle.
Tank often sits too high or the bonnet sits too low,.. causing the bonnet to hit the top of the rad. bottle. You can often see the red paint from the hood on top of that tank. In the end the rad. bottle can explode or break because of this problem. Than you will have a BIG problem, because these tanks are no longer available anymore. Best to move the tank a bit lower in the chassis or lift the hood a little bit higher if possible.

13.) Clutch.

On the Dyno the most original SZ / RZ engines will give 190-220 HP. So before tuning check first how much the engine is giving. In many SZ/RZ's you can feel that the clutch is slipping when you do a quick gearshift at high revs. Sometimes you can feel it when driving away fast in 1 st. gear.
First thing most people do is take out the old clutch plate ( not available anymore via Alfa Romeo, and it had another part number than the ones been used on the 75,... I think only the friction material is different ) and pressure group to renew it.
BUT,....before you take out the plate etc,...test first 2 other things:
1.) The master clutch cylinder, often the inside gets dirty or the rubber parts get deformed over the years. That causes problems,....for instance poor return when you lift your footh of the clutch,.. giving the "slippery feeling" from the plate.
Also a good idear to check the slave cylinders function. I still have repair kits for the clutch master cylinder in stock.
2.) There may be oil ( from the gearbox ) ecc. on the plate itself, that makes the clutch slip. If you tested the master and slave cylinders, than you can try the following.... drive away with the clutch as long as possible in a position that it slips till it stinks and smokes ! it is possible that the plate burned clean and your problem has gone ( I managed to do it at my first SZ but after that action there was a dirty smell hanging around the car for several days, but never got clutch problems with that one anymore,.... hahahaha !! )
3.) If 1, and 2 fail, than you probably have to replace the plate and cover with a better one.

clutch plate

We are testing an alternative with better friction material at the moment. Best bet for a street car is the sprung hub disc with organic lining that exceeds oem specs This disc has an organic friction lining, which incorporates a bonded metallic back plate to withstand High RPM with burst strength. Specifically designed retainers protect damper springs from both sides and significantly improve safety of the product. Center has unique feature of being assembled with six rivets for extra strength. It is recommended for street applications, autocross, rally, pro rally, off-road, and any other application where a clutch discs exceeding OEM specification is required.

clutch plate

Than I got the following remark from an UK SZ driver:

Ed, I saw your note about clutches. I found that my clutch could not take the 300bhp of my 3.5 motor, I contacted HELIX the motorsport manufacturer of clutches and found that they already have a uprated clutch for our cars. This was fitted some years ago, no trouble since. first class.

We tested the HELIX set that is "composed" by them especially for the SZ / RZ. The plate is from LUK and the pressure group from SACHS.
This sets does its job perfectely and even better priced than the original set from Alfa Romeo ( Valeo, wich is not available anymore since some years ) for the SZ / RZ.

clutch plate

14.) Mixture.

We took several cars on the DYNO,.... we noticed that the most did have a poor mixture running at top speeds, so it could not hurt to adjust the mixture to make it a bit richer.
Using 95 octan petrol is allowed, but on 98 the engine runs better, and if you had the car chipped than always use 98.

15.) Interior Switches.

!!!! First a warning is in place: !!!!

SZ / RZ versus Electronics..... I always tell people: " do not fiddle around if there is still a way to get an original part... !!!!"
Sometimes parts can be repaired, but often there will be more destroyed than repaired !!!

I drive Alfa Romeo's since I was 20 years old, so also some electronic misery from the SZ / RZ world is passing me last years.

Only on the electric front last years:
Burned out relais / clocks / km counters ( often after repairs ! ) / window winder motors / electro magnetic door switches / exploding rear screens because of mishaps in relais or switches / burned out fuse boxes / computers / and as last item: an SZ drivers headlamps, because of using other bulbs ecc.ecc.

Okee, having told that, now about the switches:

switches SZ / RZ

In those switches are little lamps and the ones from the window switches are always on ( feel how HOT the switch get after a few minutes driving ). Those lamps only have a short life span and at the end of their life they tend to get soooooooooooooo hot that the switch can melt down from the inside,... causing fuses to blow out and all kind of mishaps in the electronics and in that circuit. Because of this several SZ / RZ drivers have a spare part set in the car. Most ( all ) of those switches are not available anymore via Alfa Romeo but I still have a few sets in stock. Trying to take them apart will mostly fail and brake the switch.

switches SZ / RZ

If the window switch is bad, wobbly, melted down or if there is made a mistake in "repairing" and / or the fuse will not melt, than for instance the current can stay on the window motor, burning it during driving the car for some time.

Alfa Romeo's solution for this problem was to sell for some time switches without the little lamp ( see picture, left one is an original switch, the right one is Alfa Romeo's modification without the lamp.

led-mod SZ / RZ

The good news is that we have a much, much better alternative available: Never been used switches have been professionally modified with LED's ecc. in almost the same colour as the original lamps . Those sets are containing 3 switches ( 1x to operate the left door screen 2x for the right door screen )

*** If you have been granted access to the hidden part of the site you can ask me for more information or pictures, please let me know. ***

16.) Steering Rack ( fuzzy feeling ).

a.) In the years I have done the register I have seen this problem 6 times with members cars but now it seems to occur more often. Suddenly the SZ / RZ's starts steering like a boat !

steering rack

It is caused by the bolts in the steering rack, they are too short and sometimes they come loose, causing the problem. Check it out !!!!

front suspension SZ / RZ

Best to take longer bolts / use some loctite, or use long enough bolts to make it possible to put an extra lock-nut at the end of it where it is coming out of the frame.

front suspension SZ / RZ

front suspension SZ / RZ

front suspension SZ / RZ

b.) Another probably cause for a fuzzy feeling.

At the front wishbones the nuts can loosen over the years, best to check them once in a while. ( in the red circle at the drawing )


When parking the car you can hear a little creaking noices and the feeling in the steering wheel is somewhat fuzzy, since the front wishbones move a little bit during this action.

17.) Rear window heating.

Check with a little 12 volt lamp if the rear window heating is not still ON, after the switch is set in the off position, happened...... and than this can happen !!!

rear screen exploded

A new switch or relay be needed.
Also in the first series SZ's there was an other type of rear window heating used,... it has running the copper contact strips on the outside of the window heater at the left and right side. Those strips can come loose,... and in rainy conditions you will need your rear window heater. It can be repaired with " Contact+" from Loctite and the wires if neccesary with "Circuit+" from Loctite.

18a.) Insulating material under the SZ hood.

The foam material under the bonnet degrades with time and is not available anymore, but an alternative is.

In 2002 first SZ's had that problem. So we started to look for an alternative. We found almost similar looking material developed special for automotive use .
Similar looking stuff can also be found for other applications like airplane boxes or sound insulation for studio walls, but no one could give any answer or guarantee about heat resistance or oil / petrol resistance ecc.ecc. of that material !!
So be aware,... you do not want to have your precious car to go up in flames !!


We did some heat and flame tests, because the bonnet insulation is lying direct on top of the engine on most SZ's.
The material came out very well. It could handle high temps and when putting it into a direct flame it would give a very small blue-isch flame after some time, but after taking away the "burner" the flame on the insulation material was extinguished in a short while.

So that was even better than the original stuff Alfa Romeo used. If that is rotten on your car, than take a piece of it and hold it in a direct flame, you will be scared how quick a big yellow flame will come off that material.

The original insulations, rotten and sucked full of oil and petrol fumes/residue and often turned dark dark brown because of that over the years is making the original insulation a "time bomb" under the bonnet !

Some tests followed in several countries all over the world to see how climate ecc. had effect on this solution. Also the bonnet insulation was tested under several very hard circumstances. It was used in some SZ's being driven heavily on the track with tuned engines ecc. In those cars it happens that the manifolds ecc. will get red hot.
So over the years we got very confident that we had the best alternative for the old rotten insulation material !

How to get off the old insulation and to attach a new one.

If you want to see a larger picture, click the thumbnail .

insulation insulation insulation insulation insulation insulation insulation insulation

Hereby the best / easiest way to attach the new isolation to the car:

1.) Open the bonnet, put a sheet or something over the engine bay to cover up things and to prevent all the crap to fall into the engine bay.
2.) You can pull / scrape off the old stuff and when that is done it is all fallen on the sheet and can be trown in the bin easily.
3. ) Clean as good as possible the bonnets inside, keep the wire and enginebay light on its place.
4.) Buy some double sided tape ( best a thinner one than showed on the pictures, normally used to glue carpets ecc. ). Than devide several stripes of that tape over the surface where the new insulation has to come. We will use that tape for the first adhesive.
5.) In between the space between the double sided tape and all around you can use a good glue ( heat resistant ). In NL we have BISON heavy duty as coming out as the best solution.
6.) If the glue is on place,..than peel off the outside of the double sided tape and carfully place the insulation,..... you can pull left and right a bit on the insulation to get it better in place.
7.) During that process also press the insulation against the glue between the double sided tape.
8.) Than the heavy bonnet comes in use..... put some garden chair cushins or someting like it on top of the engine ecc.
9.) Lower the bonnet on top of the cushins and leave it there for one night,....
10.) Next day the insulation is perfectely on place.


The bonnet insulation for the SZ has 2 cut out holes. One on top is necessary for the bonnet light, the other one is most important !!!
That one is there to make room for the throttle butterfly linkage. This is needed so that the foam does not catch on the linkage and hold the throttle open !!!

18b.) Insulating material under the RZ hood.


Over the years it can loosen itself. A German RZ owner found the best glue to put this material on place again.
It is a product made by the company "Wurth" as shown below.


To take off the old RZ insulation it is not the most enjoyable work to do according to a RZ registermember:
It is a horrible job, the foil layer stayed more or less intact, but as soon as I touch the foam backing it more or less disintegrates, and turns into a sticky, oily, glue. It’s going to take a good few evenings in the garage to try to clean the hood sufficiently for the new stuff to get a proper surface to stick to. I almost wish I hadn’t started, but it badly needed done !


18c.) Silent Coat Noise Isolator 10 mm.


At many cars the rubberish material glued on the "reinforcement" parts under the hood at the left and right side has been rotten over the years.
One of our members found a good replacement, wich can be cutted easily into the right sizes needed.
The name of that material is: Silent Coat Noise Isolator 10 mm. and is available at many carpart shops. For instance at:


This self adhesive high quality isolating layer can maintain shape under pressure yet be flexible enough to trim easily in many areas of the vehicle.
Isolator 10 is water and high temperature resistant.
• Thickness: 10mm
• Sheet Size: 980mm x 600mm

19.) Mudguards and wings over the frontwheels.

Often they crack, because of the frontbumper hits the road etc, and because of this the pop rivets are being torn out.
It is best to replace the plastic mudguards if they are cracked with kevlar ones.
If the polyester wings have been damaged, than they often can be repaired ( replacement parts in polyester or kevlar are available ).
If you replace the inner wings it is best to do as follows: first drill the holes where the poprivets have to go trough,.. than glue little metal rivets / washers at the rear side,.... than you put the pop-rivet trough the hole to mount it,.. the forces on the wing will than be spread by the rivet on the back and not only by the weak polyester only.

kevlar mudguards


20.) Window wiper motor.

Sometimes it works itself loose, pulling out the too short bolts and damaging itself in that way,...Best to check it out !

window wiper motor

If you have any TechTips that can be used for Alfa Romeo SZ or RZ, I am intrested to know about that.
Please email me if you have a special Tip or solution for a problem,..thanks,...Ed.

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