adampad

Recently, I noticed the car started overheating when sitting. The radiator fans are not coming on. I know very little about 944's and could use some advise on what to check and how to fix this.

By the way it is a early 85. Does this make any difference on anything that is engine bay related?

adampad

I just did a search and came up with a lot of info. Sorry I didn't do it earlier. I know the fans should come on with the AC but it doesn't work either.

SoCal Driver

Temp switch in the radiator.

Relays. One for the "regular" fan and one for the AC fan.

Fuses. #2 and #5. If either has blown then the fan could be seized up. With the car off and cold reach down with a pen or pencil and spin the fans. If one is seizing you will know by it's resistance to rotate. Or it may not rotate at all. An upgrade to the six bladed fans from the later models is worth while. Get both fans in the housing with the wiring harness to the switch then splice it into the 85's harness.

soundboy4

check the thermostat under the radiator first. if that doesn't work it might be the relay

adampad

I was out poking on it a while ago. I was suprised to see it has the 6 blade fans already! They seemed to move freely too. The passenger side fan is very close to the lower radiator hose though.

On my other car, I can just unplug a sensor and the fans will run nonstop. Is there anything like this on the 944?

GOBOGIE

The thermostat relay that plugs into the radiator just below the top radiator hose is usually the problem. It's like $30 at your local parts store.

SoCal Driver

You can pull the wires on the temp switch and jumper them toghther. Fans will run when ever the key is on. Supposedly a different relay for the AC -- factoryt update. You may have the wrong one.

Good that you have the six bladed fans. Much better motor brush design and it's front ball bearing is sealed. Quiter also than the three bladed fans.

You can rig up a toggle switch and force the fan relay closed. Seen a few on other 944's over the years.

Zero10

I just fixed an issue on an 83. The fans were not running on it either.
Check the connections at the thermoswitch. These were corroded very badly.
It may or may not be the problem, but it's easy to check.

Yabo

not to hijack the thread, buta quick question. anyone notice if at idle and the fans kick on, the alternator gauge reads about 12?

83na944

At least one fan should come on with the AC and ignition on. Even with the car not running and a bad thermo switch. Must be a blown fuse, bad relay, or wiring problem.

Check this web site under workshop manual and cooling system for a good fan troubleshooting guide
http://www.clarks-garage.com/

83na944

Devon, do you mean that the voltage drops to 12 v at idle when the fans kick on? I don't have a voltmeter in the car, so I don't know if this is normal. But the battery voltage is usually more than 12 v and the alternator usually charges about 13.5 v. Maybe you need a brushes and voltage regulator.

Zero10

Hmm... 12V on the gauge, or measured at the battery?
I know my gauge reads too low. when it's at 13.5V the gauge reads a hair above 12. So yep, mine goes down to the 12V mark when the fans kick on, or when I crank up the interior fan, or turn on the lights. But the electrical system is still at 13.0V, at least at the battery it is.

If it really is 12V, that sounds pretty low. What is the voltage at an idle?

83na944

Good point Zero10.

Yabo

Well. my voltage at idle is somewhere around 13.5 or 13. It never really goes down at all even with lights on or whatever. But the toher day when i was sitting idling, and the fans came on, the voltage meter in teh instrument cluster went down to 12.

Yabo

btw, my battery has never died on me, nor been weak.