Running Hot? Check cooling relay.

[anotherblack944]

I've see so many posts lately about 944's running hotter than normal with a common reply about bleeding the system. This was also posted in another thread but thought it deserved its own "tip". My appologies if this has been posted before.

If you've already done that (bleed) with no success check your "cooling relay".

I have a 84NA that suddenly started running between third tick and solid yellow on the temperature gauge even if only 80 degrees. I could hear the fan come on while driving and observed it running in idle with engine off. Fuse #3 checked out OK. Shop tested engine temp sensors and they checked out OK. They then discovered that there was "no power across the fuse box". They pulled the cooling relay and opened it up. One of the contacts was burned and not even touching (also scorch marks inside the relay case). In my case it was part # 944.615.113.01.

What a change! Now runs between 1st and 2nd tick even at 93 degrees. Creeps a little higher at idle in traffic but drops right back down to the 2nd tick as soon as the fan goes to high speed.

[binky]

What does this relay do?

[divezic]

The cooling fan relay turns on both cooling fans on the radiator. When the relay goes bad, only one fan turns on and at a lower speed (due to a resistor). Check out the wiring diagram...
http://www.pelicanparts.com/944/electrical/944_84_AC_2.jpg

This post makes a good point; troubleshoot a problem and you might find out it's an "easy" fix. Although, if both cooling fans are working properly then it is not a relay problem.

[binky]

OK thanks. Both of my fans are going, so I presume I have a good relay. I am jealous of his cool running 944, I live where it's 90 today and my car will get quite hot in stop and go traffic. I need to keep researching the problem. Just don't want to toast my engine.