Abnormal Temperature Reading After Doing Headgasket
 

I recently did a head-gasket job on my S2. I did a lot of miscellaneous stuff while I was in there, such as: valve grinding, valve stems, cleaning contacts/grounds, etc. I finally got it all back together and it runs very well, except instead of reading 1/4 for the temperature it reads 1/2 and sometimes a little higher (When warmed up). It does not change no matter how I vary the speed. When I did rev the car high it went back down ONCE but then promptly returned. I bled the system several times. I was thinking it could be a faulty sensor/connection or possible a thermostat but I was wondering what the general consensus is (or if you thought of something I didn't).

Maybe your ground cleaning exercise changed the way your gauge is reading.

Either way, I don't think 1/2 is a problem. Drive and enjoy!

How did you bleed the coolant?

x2 on the bleed....

Rasta may be correct.

Does the temp go down when you turn on the AC (yeah in the winter :))

Is the cam belt tensioned properly?
-----Do you know how to do the WP pully test?

When you had the head off, did you clean the galleys between the cyl walls and the block?

Maybe it is a thermostat issue. Only use OEM and not a NAPA or store brand.

GL
John_AZ

I checked the manual and it says its fine to be in the middle. Where does your car read (1/4 or 1/2?) I'm starting to think you may be right.

I used the gravity method, which has always worked before when I flushed the system.


John,

It was about 75 Degrees yesterday and I did turn the AC on when the car was idling (to turn the fans on and see what the response from the gauge is) and the temp dropped to 1/4.

When I did the Head-gasket I changed all the belts and tensioned them using the Factory Porsche Tensioning tool. I do not know how to do the WP pully test, could you please explain? I did clean the galleys between the cyl walls when I had the head off (Very difficult, but I tried my best). I put a new OEM thermostat in about a year ago, but I heard that they can go bad for no reason anyway.

75F in CT? Southern part? ;)

When I refill my cooling system, I squeeze the top hose until a drip comes out of the top cooling water hose outlet sealing plug. After a couple of trips I top off the coolant through the plug.

You have the P9201 tool with calibration bar. The best there is. For many, other tension techniques are used. 90 degree twist, Krikut, Rasta has his wife set the tension by "feel".

I get it close with the later "spring tensioner" and check with the WP pully test. Even with the P9201 guage, a new belt may be tensioned too tight and ruin a WP pully seal or bearing.

http://forums.pelicanparts.com/uploa...1270306280.jpg

Retension at 1000-1500 miles

GL
John_AZ

The S2 or any late model 944 has a stock dual thermofan switch rated at 92C and 102C. The radiator fans run in slow speed when the coolant temp gets up above 92C/198F. If the coolant temp keeps rising to 102C/216F, the radiator fans will run in high speed and bring the coolant temp down below 102C, then run in slow speed and turn off once the temp drops below 92C.
So, if both radiator fans run in slow speed, it should bring the coolant temp below 92C/198F.

The slow speed fan operation on the S2 is enough to keep the coolant temp just below the 1/2 mark. If the temp goes halfway, it's either only one or none of the fans run in slow speed or the fans only runs in high speed.

If you look at the late model temp gauge, 92C is just below the 1/2 mark.
http://forums.pelicanparts.com/uploa...1270326387.jpg

Let your car idle until it reaches operating temp. Open the hood and observe what temp the radiator fan runs in slow speed.

I checked the fans and they were not running. I also changed my voltage regulator. My other one was just about ready to go. Maybe I am getting more current so my gauge is working properly? My car seems to start better and it seems like the battery has more juice. John, I will check the Water pump sometime soon.

Thanks everyone for your assistance so far!

"Let your car idle until it reaches operating temp.

Open the hood and observe what temp the radiator fan runs in slow speed."