06stef

I go to the garage, the computer does not detect any fault, temperature probes are ok.

So it remains to change the thermostat or water pump.
I have had some air bubble problems into the circuit, after flush coolant...
I hesitate to change this elements, myself....

Macster

Well, if you are of the opinion the coolant temperature is too hot there's not much else...

Before you start, you must be sure the fans are running and blowing the same amount of air.

I haven't re-read my previous posts so I might be repeating myself, but my 996 Turbo had a fan motor shaft snap. The motor continued to run but of course no air was being circulated since the fan wasn't being turned.

Might mention I found this not by the coolant temperature increasing, at least not at the gage by any noticable amount. I discovered the fan wasn't turning by the change in the fan noise. This prompted me to get out of the car and then I found that while the driver side fan was blowing copious amounts of hot air out there was no air flow at all at the other side.

The same car when I had the car in for what proved to be a leaking water pump, we found the driver's side radiator fan while we could hear it running was not blowing nearly the same amount of air out. The tech checked the ECU for fan stage errors and none were present but the fan motor was drawing more current than the other one and I had him replace it.

Again the engine coolant temperature, at least at the gage, was just fine. I caught a whiff of anti-freeze which prompted me to bring the car to the dealer. This was from the leaking water pump.

If you are sure both radiators fans are running and both are working/blowing the same amount of air then possibly the T-stat has stuck partially closed.

As I recall advising you you can check for this by getting the car in the air and letting the engine idle and carefully checking the hoses from the water pump to the radiators and back again. You want to feel them get warm, then hot as the T-stat opens from the hot coolant. You also want to feel the returns to make sure both radiators cool the coolant about the same.

If you want, get a infrared sensor that can take temperature readings by just aiming the gun at the item.

Something like this:

http://www.labdepotinc.com/Product_D...FZBgfgod06wAwQ

Or you can just replace the water pump and T-stat.

However, if you are hesitant about replacing these yourself seek out a reputable shop and have this work done. The cooling system will be refilled using some kind of vacuum lift and there will be no air pockets.

06stef

ok i changed the T-stat
test on the road = 90° Celsius
but I have noticed that the valve on the expansion tank it open
(So under pressure) is this normal ???

cold engine, I open the cap the expansion thank coolant.
"pfffffffffff" noise pressure..
check level the coolant is ok.
but if I ride again, the valve on the expansion thak it open...

DBJoe996

When the engine is cold the valve is down. When the engine is warm the valve is up. Normal operation.

06stef

thanks you very much for your helps regards