potent951turbo

I'm at a loss on this one. I am no newbie when it comes to 944's so I have tried all the tricks I know.

The car is an 87' 944. The first problem is when you shut the car off both the fans will run at full speed for about 10-20 minutes at least, sometimes more. The second problem is that if the temperature is over 90 degrees outside the car will heat up to about 75% on the gauge (normally runs at 25%) before struggling to cool back down to maybe 50%. The car has been running a low temp thermostat/fan switch for close to 4 years with zero problems before this. I just replaced both of those with brand new ones, new waterpump, I have swapped out the fan relay with a spare and one out of my 951, the resistors look perfect as does the wiring to them, and I have bled the system on numerous occasions with no solution to the problem. Does anyone have any other ideas?

DarylJ

Your cooling fan relay is bad, and likely the coolant temp sensor in the radiator. I know you said you swapped it with another relay, but are you positive it is good? The 75% and struggling to get down sound exactly like the low fan speed isn't working and it only comes on high, and that seems to be quite a typical way for a fan relay to fail (I have two "spares" on the shelf that do exactly this).

If you start the car and watch it heat up, do the fans ever come on low? Or do they just stay off until you are way hot and then switch from off to high?

Edit: Another thought.....the last time I dug through the wiring diagrams for this was a while ago, but I recall that other than wiring and fuses, the on;ly thing controlling how long the fans stay on after shutting the car down are the temp sensor in the radiator, low speed resistors, and the fan relay. Also, the wires going to the low speed fan resistors like to cook, so I'd be inspecting those.

potent951turbo

The temp sensor is brand new and went in with the new waterpump just a few months ago. I suppose there is a chance it could be bad, although seems unlikely as the old one was still fairly new and I still have the same issue with a brand new one. The relay I have swapped in was out of my 951 which operates just as it should, I have even put the relay in my 951 from the 944 and it operates just fine in the 951 as well.

DarylJ

Sounds like you have it reasonably covered. What about the fans running on low? Does that ever happen?

If not, I'd say it's time to check out those resistors and the wiring.