S2 engine temp. problems

[Simons]

Hi guys

I have a big problem with the temperature of my s2 3b, the problem is this:

The water gauge shows 110ºC and sometimes something more...I changed the 4 contact water sensor for a new 3 contact, becouse the 4 aren't available and mine was very bad condition...sometimes don't sent signal...other sent full signal...one question, what I need to do with the lost wire?? I cancelled it.... or it must be attached with another one??

I changed thermostat and the radiator thermal contact who starts the fan

I changed the dashboard to test the water gauge, but it's good

Is possible that the main radiator are very dirty inside and the coolant isn't circulating well...??

The 3 contact sensor are deficient (I bought in 034MTS) or bad connected( I'm going to test by the wire schemes becouse the brown connect was very bad and I used faston(?) connectors, but I think is good)...or I must connect the free wire with another one

Any idea

Thanks and sorry for my poor english

[jorge s2]

hello simons i thing you should the main radiator first is an easy job . about the conectors i have no idea . cheers an good luck.

[jorge s2]

sorry i want to say clean the main radiator

[Rusty]

English is good there

Air lock, system pressure leak or head gasket if you've gone through almost everything else... 3Bs had paper gaskets so won't be a surise if it's gone.

[chezz]

Thermostat fitted the wrong way around...

[Simons]

sorry i want to say clean the main radiator

I don't know if these is the main reason...but I think it's very dirty becouse the top is hot and the low is cold...tomorrow if I have any free time I will remove it and then I will carry an specialist on cleaning water radiator

English is good there

Air lock, system pressure leak or head gasket if you've gone through almost everything else... 3Bs had paper gaskets so won't be a surise if it's gone.

Thanks Rusty

The water circuit hasn't got too much pressure and there aren't oil rest on the coolant...but the head gasket, I think never changed, is 20 years old and 230.000km...it isn't brand new the paper(asbestos??) gasket...I have the metallic Rs2 + ARP head bolts, but isn't the time yet, becouse the head will be checked and repaired when I remove and I don't stop the car for a long time...yet

Thermostat fitted the wrong way around...

No chezz, I think it's impossible (or almost..) to fit on the wrong position, and the temp. on the radiator is the same than before and I changed for this reason...hot on the top and suspiciously cold down...it will be possible to be deficient...I don't know but I think not becouse make the same...

Thanks!

[Knight Rider S4]

Temp switch is ok for 3 pin as earth through switch now rather than wire (extra wire)

Overheating as mention above

But check the water pump is not screwed

Expansion Cap

Head gasket failure possible , would pressure test system and see if it shows anything

[Simons]

Temp switch is ok for 3 pin as earth through switch now rather than wire (extra wire)

Overheating as mention above

But check the water pump is not screwed

Expansion Cap

Head gasket failure possible , would pressure test system and see if it shows anything

I don't understand you very well...is the extra wire good if it's cancell?? or I must connect to earth

I think the water pump are good becouse there aren't any coolant leak and the water flows...I changed it 2 years ago and it has got aprox. 20.000km...

I'm going to remove the main radiator and then I will put a 7A radiator that I have, to test...becouse my expasion glass are dirty and the coolant that I removed was oxide...

Thanks

[Error404]

try flushing the coolant system with Tri-Sodium Phosphate

[chezz]

No chezz, I think it's impossible (or almost..) to fit on the wrong position, and the temp. on the radiator is the same than before and I changed for this reason...hot on the top and suspiciously cold down...it will be possible to be deficient...I don't know but I think not becouse make the same...

Thanks![/QUOTE]

It is totally possible! Hot top hose and cold bottom hose point to the thermostat being jammed closed if it is not fitted incorrectly. Temporarily remove it(test it in boiling water) Run the engine without it and see if your temp problems improve.
Dont waste your time changing Rads until you have eliminated this, as a highly likely cause.

[chezz]

If you think it is your main radiator pull the bottom hose off and watch all the fluids run down the drain. This will solve/answer any questions regarding the rad being blocked.

[Simons]

try flushing the coolant system with Tri-Sodium Phosphate

and what I need to do?, I mixture with the coolant, in which percentage? is aggressive with the head gasket and the water hoses?? my coolant system needs too much a clean...but many products are very agressive

It is totally possible! Hot top hose and cold bottom hose point to the thermostat being jammed closed if it is not fitted incorrectly. Temporarily remove it(test it in boiling water) Run the engine without it and see if your temp problems improve.
Dont waste your time changing Rads until you have eliminated this, as a highly likely cause.

I think that you say that I could put the spring side on the wrong way.....I removed it and I installed the old thermostat but I removed the system and I only used the frame and o-ring. I didn't remove the radiator, I introduced water from down to top, the radiator was dirty but wasn't blocked and the overheating disappear.

But the fan didn't start, I inspected the electric system, all good, and I used a fuse with a wire to bypass the fan connector, the 1st and 2nd speed ran....I saw on the new radiator thermal contact that the scheme was diferent...this was + 1 2, and audi use + + -

I'm going to buy a new thermostat and radiator thermal contact

Where can I buy a thermostat and radiator thermal contact more cold than OEM?? or the reference and mark

If you think it is your main radiator pull the bottom hose off and watch all the fluids run down the drain. This will solve/answer any questions regarding the rad being blocked.

Finally it wasn't blocked, it was very difficult but it wasn't imposible

Thanks

[chezz]

Good to hear you are making some progress!

[Simons]

Thanks

Do you know where can I buy a thermostat and radiator thermal contact more cold than OEM?? or the reference and mark??

[chezz]

Thanks

Do you know where can I buy a thermostat and radiator thermal contact more cold than OEM?? or the reference and mark??

Would it be advisable to change to a different rating of thermostat?
I'm sure you will be OK once the new OEM thermostat is fitted.
With the engine in this state, you have a good opportunity to flush the block/rad out with a hose pipe to remove any crud.