ehall

Need a little help. I drove around for a couple of hours running errands. The cooling fan was on as it is supposed to be, when I got out of the car. After the trip I got out, came inside and didn't go back to the car for about 2-3 hours. Somehow I didn't hear it running, though I am now certain that I tuned it out.

Fan ran all day and, obviously drained the battery to a point that it wouldn't start. When I tried to jump it, it dawned on me that the fan had been running more than normal. Though the car would not start, turnover etc., the fan continued to run at alow rate, and continued draining the battery. After pulling the Turbo h2o relay, and the AC relay (g17 and G19) with no change, I pulled the engine fan realy,(g10). That stopped the fan motor from running. I then jumped the car without the G10 relay installed and it started up perfectly.

So... What caused the always on condition? WAs it a faulty relay, or am I dealing with a thermostat issue, or is this about to get stupid expensive? Though I'm no pro mech, I feel atleast reasonably sure that I can fix trhis with a little RENNLIST help. Please let me know what you think. P>S> How much heat can our cars handle safely, in terms of the temp gauge reading of a stock 86 951? I don't do any daily commutes, and only trips within say 5 to 10 miles a few times a week. Let me know what your thoughts are on this thanks.

Sam Lin

Most likely the radiator thermo switch, in the driver's side upper corner of the radiator. They tend to fail "On."

Sam

ewainwright

Don't play with an overheating issue with our cars. I'd change both thermo switch and the rely. Personally, I'd leave the fan running if I must drive it home. Then park it. They don't tolerate heat well at all.,

Jaak Lepson

It's the switch in the rad. To shut it off, open the hood and remove the relay in the fuse/relay box after a minute or two. Remember to put it back in before you start the car again. It's a half hour repair to replace the switch. Remember to burp the cooling system after it's replaced.

Jaak Lepson

ehall

O/K. That's what I thought about the heat issue. Here's a new twist. I put the realy back in, started and ran fine, didn't stay on after. I only drove 2 blocks and back so I don't think the fan would have come on in a cool night condition. It also didn't stay on when I stopped at the Grocery store(that was the aforementioned 2 blocks. No constant run condition.

Jaak Lepson

Switch could be on it's last legs!

Jaak Lepson

d.wheel

to jaak lepson
So how do you replace the rad. thermo switch in half an hour ?
How do you gain access ?

hosrom_951

The best way is from under the car, this link would help you:

http://www.clarks-garage.com/shop-manual/cool-05.htm

d.wheel

to hosrom_951
many thanks for the info. links.
switch replaced without to much trouble.
somewhat more than 1/2 an hour though.
regards,
d.wheel

Jaak Lepson

It is when you have a Porsche Garage at your service. I did the work under their supervision ... friends of mine

Jaak Lepson

toddk911

Anyone using the lower temp switches/thermostats??

hosrom_951

I am running an 85~91 (standard runs 91~112) and thermostate is also set on 80.

In celcius that is