Porsche Repair: another porsche 944 overheat, electric cooling fans, k n air filter

Question
Hi Dave,

I bought a used porsche 944 (1983, first year of 944) recently.  Aside from needing to get the A/C looked at, it was fine... until it started overheating easily.

As you may know, it has a back-hose-thing where the water or coolant leaves when it gets too hot- at first I was using water, then I tried real coolant and no improvement.

I'm not sure if the fan is coming on- it used to come on reliably even after I turned off the car- maybe it's the thermostat-

only thing I changed was to put a K&N air filter in- but I've been told if anything that would cool the engine- is that true? seems that more air would increase HP which would heat engine, not cool it, right?

how do I diagnose if it's the thermostat or what - rather than just replacing the thermostat or hardwiring the fan to the battery... ;-)

Thanks,
Brian

Answer
Hi Brian.

If your two electric cooling fans aren't running after you turn off the car...and you're overheating...don't drive the car until you replace the fan relay or the A/C relay or both.  These fans are related in the sense they should activate whenever the A/C is turned on or they should activate whenever the water temperature reaches a certain temperature and should not stop until a lower temperature threshold is reached, whether you turn the car off and leave or not.

There is a separate relay for the two functions so you'll have to have them each tested...or just buy two new ones and get it over with.  I know...they are very pricey for relays.

Dave