amex859

both of the fans start running constanly at start up. this happens even if the car has been sitting for days .
any help would be greatly appreciated

thomasmryan

AC pressure switch or the radiator fan switch. unplug each individually. if the fan stays on, suspect the relay.

oz968

My money is on the relay

Dave O

My 968 started doing the same thing this afternoon. It was fine this morning. Outside temp is in the upper 40s F. Turn the key to on, not starting, they run. Fire up the engine they run. Turn off the car they stop.
I pulled the relay, turned the key to on and they didn't run. Plugged the relay back in and turned the key to on and they both ran at top speed. Both cases the car was not started.
I'm not sure I've diagnosed anything. Can I leave the delay out and drive the car? Leaving the relay in, is it ok to drive the car with the fans running full speed?
As you can see I'm lost. Any advice will be appreciated.
Dave

Yogii

Dave,

I'm a novice, so keep that in mind. I keep an eye on my alternator. Usually it is right at 13.4 on my cluster gauge. With the radio, lights, and A/c on it goes down to about 12. As long as they go off when you turn the key off.
Mine usually run about another 30-60 seconds? I once drained the battery because the under hood light switch never turned off!

-Yogi
AKA 968 Novice

Dave O

Thanks Yogi. I did watch the gauge and it stayed steady at over 12. I think it's down a bit from just just over 13.
Everything turns off when the key is turned to off. I did order the radiator switch from an eBay vendor last night (<$10 free shipping). I'm hoping it gets here before Weds as I have the car going in for an oil change then and the mechanic would be able to put the radiator switch in while it's up on the lift
I've been reading about how to test a relay so I'll check the relay to see if it's ok. I feel caught between a rock and a hard place... The switch is $10 but kind of a pain to get at, needing to have the car elevated to reach it. The relay is easy to swap out but pricey, a salvaged or parted out one is $70-75 and a new one is well over $100.

I'm working on the assumption that it's better to have the fans running thus keeping the engine cooled rather than pulling the relay thus disabling the fans and risking over heating the engine. Until I get it sorted I won't drive the car too much.
Dave

fossberry

If the relay, check out my post on the subject:
https://rennlist.com/forums/924-931-...urning-on.html

Dave O

Thanks fossberry. I'm definitely leaning towards the radiator switch. Just checked the car this morning, stone cold, and turning on the ignition(not even starting the car) the fans spun up right away. I tapped the relay to see if it was stuck and there was no change. So I'm just waiting for the switch I ordered to arrive. Ah, the joys of owning a 27 year-old car.
Dave

Yogii

+1 sad but true...

-Yogii
AKA 968 Novice

Jim C

I've got a new relay and a new switch on the way. I plan on replacing both, just to be on the safe side!!

Dave O

I replaced the radiator thermo switch yesterday afternoon after receiving my new one in the mail. This thread provided guidance for doing the job from above:
https://rennlist.com/forums/924-931-...m-the-top.html

The switch was <$10 but I spent had to spend around $14 on a 29mm deep socket and a 3/8 - 1/2 adapter !

After staring at the car for a while and gathering the appropriate tools, rags, work lights and courage I dove in. I had pulled the car onto a small tarp so the coolant that missed the catch basin would stay off the garage floor. I carefully laid rags/towels to prevent any screws or bolts to be removed from falling down onto the under pan which I had not removed. (I had dropped a part down a disposal during a kitchen faucet repair the day before so I was taking no chances on this job.)
I lost a minimal amount of coolant. Unfortunately some that missed the basin and flowed off the tarp so I had some floor clean up afterwards. I had more of a problem reassembling the air filter box with the front air intake that anything else (helps if you do things in the proper order).
I topped off the coolant and drove around the block. I then left the car running in the driveway to bring up the temp. The fans kicked in properly, ran for while after the engine was shut down and then turned off. No leaks, no over heating, proper heat in the cabin when it was turned on.
Things are great in this part of the universe!I
Dave

Yogii

My experience is that the tarp is never big enough to catch everything...

Glad she is up and running right!

-Yogii

Dave O

Thanks Yogi. I'm really no mechanic but I've decided to try to do some of the work on the Porsche. I know what I just did was pretty "101" but I found it very satisfying.
One thing to note is this switch indeed needed a 29mm socket though a 30mm is noted in some threads & videos. I tried a 30mm but found it to be too big. I'm not sure how consistent aftermarket parts are in size.
Dave