drraulduke

Sorry for the long description, but i think it is best to be as specific as possible.

I have an 86 944 N/A. The previous owner mentioned to me when I bought the car that he had a "turbo" cooling fan placed in there (he was going to build this up as a track car, but never did). It is my understanding that the fans for turbos and NA's are the same, as I cannot find any cooling fan that is specific for turbo 944's. Everything has seemed to be running fine except that the high speed fans would kick on shortly after the low speed fans, never allowing the engine to even come close to the 102 C mark, which I liked because it kept the engine running nice and cool. Recently, the low speed fans stopped working when the car was off and the ignition was off and key out. Today, I heard a light "buzzing" noise coming from the fuse box after driving the car and located it to the cooling fan relay. I unplugged it and then re-plugged it in and, viola, the low speed fan turned on with the car off and ignition off. My questions are:
1)Could the previous owner have installed a different temperature sensor and re-wired the cooling fans in the car so that the high speed fan turns on early and keeps the car cooler?
2) Could this change cause damage to the cooling fan relay, which would explain why it was "buzzing?"
3) Could this simply be a faulty relay?

Thanks for any help and suggestions.

951mcomm

I am not a guru but here is what I have found

there a 3 types of thermofan switches
1 has a low temp
2 has normal temp (factory standard)
3 high temp

racers like the low temp to keep the engine cooler causes the fans to come on early and often, it bolts into the radiator. I would buy a new one @$35 just for a piece of mind.

As for the relay it may be getting more use and the solder from what I hear over time can crack causing a poor connection which may be your buzzing.

But if the thermofan switch is in good shape you should should hear nothing when the car is off.

drraulduke

Thanks, 951mcomm. I'll take a look at the thermofan switch to see whether it is new. Most likely it is new because I think, by what you are saying they probably put in a low temp switch because he intended to use this as a track car. I'm going to test the relay tomorrow with my multimeter to determine if one of the soldering joints is cracked. A new one is so expensive ($225) for what it is so i'm hoping to find a used one from someone who is parting out a car or a local porsche shop.

Grandpa#3

Since you live in Atlanta and the summer is getting near, I would keep the lowest thermostat switch in the radiator. The fan should run for a while after you drive the car as the heat builds up when the engine is shut off. The large fan relay can be taken apart and the solder joints freshened up. Just don't get carried away with the solder gun. Get a spare relay before you tear into the old one. I keep a spare fan relay (used) along with a new DME relay in my glove box. The first link is what the resistors look like up behind the clove box. The wire insulation can get hot and flakes off. Replace wires if necessary.

https://rennlist.com/forums/attachme...t-im002964.jpg

http://www.944online.com/cgi-bin/for...num=1222698188

http://www.clarks-garage.com/shop-manual/cool-01.htm

Cheers,
Larry

steve944online

If you need a relay I have a good used one for $75 it came out of a running driving car.

drraulduke

I might take you up on that offer of the used relay, however, I just ran all the tests on the relay according to clarks garage and it past all the tests. I'm thinking it's either on it's way out or it's perfectly fine and it could be the slow speed fan resistor that is bad.

drraulduke

Thanks for those great pictures Grandp#3. You've been a great help on several of my projects!