TaboII

Interesting recommendation from an old Porsche mech I though I would pass on for all to contemplate. I am going to set this up during my upcoming water pump change weekend after next.

Here is the idea. Have you ever noticed that in stop and go traffic your car seems to get very warm! Have you been driving around town during the summer to find that your temp gauge is creeping closer to the dreaded red mark on the dash? Well here is what I plan on doing about that.

As many of you already know with the later model 944’s and others. The fans only come on to bring the engine temp down to the 2nd bar right when it hits the 3rd bar on the temp gauge! We all know the cars run much better when cool so why wait till the temp gets to that hot mark to lower the temp. In cars with the rabbit switch with three connection crossing the two outside connections to ground turn on the fans to high until you break the circuit. Well I am going to take this one step further. I am going to add a manual switch using an old sunroof switch to create this circuit in order to manually turn this on and off from inside my car. Further I am thinking about adding into the circuit a thermal activation switch in the works, to automatically turn on and off this switch at a much lower temp than the original motor temperature switch is set to. Whala no more creeping temp gauge and your will be able to prevent unnecessary engine wear and tear just because of a little to high temp in the radiator and or motor. Also with a thermal switch in the circuit you can leave this circuit turned on and forget about it or only turn it on when you think you need it. During the winter you can completely turn this off and run at normal temps unless you feel for what ever reason you need the extra cooling power.

Ok there is it. I have not worked out all the details yet but I am sure this will not be to difficult to figure out for some of you out there.

What are your thoughts on this idea?

I am interested to get input from the experts out there.

Thanks Keith M
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951Tom

I'm far from an expert.....but I think your fix is a good idea but it's really working around the real solution. On my car, I've got lower temp thermostat and fan switch. In 100+ degree, with the a/c on or off, my gauge is always at or a needle's width above the first skinny line. And I've got a turbo which if you pop the hood on a hot day....be prepared for a big BLAST of heat. I put in a new radiator and the PO did the pump. A needle creeping up towards hot means something is wrong.

Bob S. 1984 Silver

I like your idea; gives you manual control of the fans. However, one suggestion. Make certain the switch is wired to a circuit that is cut off when the ignition is turned off. This way, you eliminate the risk of "forgetting" to shut it off and being surprised by a flat battery.

BTW...I added a relay and an indicator light under the dash to tell me when the fan(s) are running. Nice to know.

Cheers!!

Bob S.

DennisR

Wouldn't just turning the AC on do the same thing? It does in my car.

951Tom

I know later A2 VW's have a under-hood temperature sensor that is tied into the radiator fans. I've wanted to add one to my 951 but worried it would run the fans too long & drain the battery. Maybe you could use this temp sensor for yours?

pete944

My a/c doesnt work anyway (for now) so I unplugged the wire to the compressor and when the car starts to run a little warm, I hit the a/c button and the fan goes on. Since alot of us don't have working a/c this may help someone.

Pete

PorscheG96

[quote]Originally posted by DennisR:
<strong>Wouldn't just turning the AC on do the same thing? It does in my car.</strong><hr></blockquote>
It's a trade-off. While both fans do come on the cooled water is drawn away from the engine...

TaboII

Ok Just to clarify.

As far as my mechanic has explained this to me there should be no trouble running the fans for periods of time. Of course you would not want to just run them all the time that would not be good for the fans. This switch would allow for better cooling control in heavy use situation such as autoX or Saturday night runabouts. Thus giving the operator control over when the fans are on to further protect the motor. The idea to use a thermal switch would only allow a greater protection from over heating. If there is a original problem then adding this switch is not a band aid and the problem would need to be resolved "Of course" but as I look at it anything to avoid costly damage and the following necessary work is worth the effort.
protection from over heating..