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Badger · Joined: 04 Jul 2006 Posts: 17 Location: Madison, WI

Hey all, I would like to start off buy saying that just by reading a few pages of posts has made me realize that I am going to really value the extensive resource of knowledge that is presented here. I want to thank you all in advance for that! I just joined the club with my first 931, I'll post some picturess as soon as Im finished detailing it. Its the two tone silver/grey with black vinyl and the man-hole cover wheels. It does however have a few issues, firts of which I would like to address is the overheating. The fans are not coming on, and I read Chaos' post where he had a similar problem, and I think I need a new radiator temp switch. I think this because I jumped then fan by closing the switch myself with a battery jumper and the fan started turning. I suppose this means that the switch isn't getting the message that the coolant is getting too hot and the fans aren't going on? If this sounds right, I was hoping someone would know what part number that is or where to find a replacement for a decent price. Thank you in advance for your time, I dont know if I would feel as comfortable buying one of these cars without this forum : )

Belgian924t · Joined: 07 Jan 2006 Posts: 104 Location: Belgium

Hello,

welcome here.

The temp switch you can by at a good autostore or at a Volkswagen dealer. Remove the bad switch and take it to the shop as an example.
The new one will probably cure the problem. Is the car getting hot during driving or only at idle speed? Take a closer look at the cooling system after you replaced the switch.

Greetz
_________________
'79 931 with Carrera GT look
'86 944 turbo (sold)
'88 944 turbo S (sold)
'85 911 Carrera 3,2 (to be restored)
'80 911 SC "SOLD"
http://www.cardomain.com/ride/2224272

Badger · Joined: 04 Jul 2006 Posts: 17 Location: Madison, WI

Actually, I drove the car home (over an hour long trip) without the temp gauge getting past the third line. But it was highway driving. If the car is left to sit and idle in city traffic, Im sure it would overheat. The fans didn't come on at all on the drive home.

D Hook · Joined: 02 Nov 2002 Posts: 3158 Location: Omaha, NE

Welcome to the board. Be sure to post your location so we know if you're overseas or in the states. Put the year and model of your car in a sig line so people know what car your talking about. Makes a big difference in the advice you get.

That switch is located in the upper driver's side corner (USA LHD) of the radiater. Large diameter plug with two wires going to it. You can find them on ebay pretty cheap new (about $14 shipped in the states) or you can get them form performance products for more $. But I'd check your local parts store first, like the previous poster suggested, because they're pretty common and are used on other model cars, too.

Sometimes previous owners have butchered up the wiring on the radiator temp switch instead of just paying for a new sensor, which can cause other problems for your cooling system. After you replace the switch you'll be able to tell if anything else is suspect like radiator cap, etc. Take a close look at all the electrical connections, be sure they're clean and tight and protected w/dialectic grease to keep away the corrosion.

If you HAVE to drive the car, you can join those wires to turn the fans on. They'll run all the time but better than overheating and blowing a headgasket. But it's best to try to fix it right so YOU don't butcher up the wiring.

Good luck and looking forward to the pics, too!
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'80 924 n/a SOLD

gohim · Joined: 02 Nov 2002 Posts: 4459 Location: Rialto, CA

You can also turn the ac on, which will switch both cooling fans on if all of your ac and cooling system wiring (other than the thermofan switch) is in working condition.

When you go to buy the replacement thermofan switch, make sure that you get one that is designated as a lower temperature operating type.

The stock switch activates at 190-195 degrees F.

You want one that activates are 175-180 degrees F.

Do not buy the one that activates at 160 degrees F. This is too low, and your heater and defroster will not work correctly.

Badger · Joined: 04 Jul 2006 Posts: 17 Location: Madison, WI

Thanks everyone for taking the time to help me out...Im picking up my switch tonight so hopefully I'll be able to start driving my new baby around town. I have a lot more questions, so I hope everyone wont mind the multiple topics I post. Again, I appreciate you guys helping me out.
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1980 931