Cooling Fans

[Thunder-71]

The cooling fans on my 1984 944 do not come on resulting in engine overheating. If I turn the A/C on though, they do run and the engine cools. I am suspecting the heat sensor. I am a novice and any help or sugestion will be greatly appreciated.
Thanks a lot.

[mattdavis11]

On the upper driver's side of the radiator, there is a screw in brass plug which has two wires attached. Take a paper clip and jump the two terminals, you can leave the wire leads on if you like, it doesn't matter. The fans should come on when when you turn the car on. If they come on and the wires are jumped, the thermo fan switch is bad. It's the brass part you by passed.

If the fans don't come on, you have a bad cooling fan relay, or a short. Let us know.

Welcome to Pelican!

[onZedge]

DON'T JUMPER those permanently!!! The jumper will cause the driver's side fan to run all the time in low speed when the engine is off.

Replace the temperature switch after checking to see if the wiring is OK.

[bearone2]

i replaced that switch on the '84 on ramps, deep 1 1/8 socket and didn't remove fans or shroud.

i didn't drain the rad and only leaked water down to the switch(did get a little wet but water was cold).

refilled/bled and the fans worked as advertised.

[smkn951]

picture of the item to be bypassed or jumped please......
TIA
Carl

[kfanazini]

You don't need a picture, Matt told you where it was.

"On the upper driver's side of the radiator, there is a screw in brass plug which has two wires attached."

Originally Posted by smkn951

picture of the item to be bypassed or jumped please......
TIA
Carl

[curtisr]

Originally Posted by smkn951

picture of the item to be bypassed or jumped please......
TIA
Carl

I hope this helps. It's from the manual, however, it does say for 1987 models on... Regardless, you can search this forum and see that it is a topic that pops up from time to time and may find something better. Anyways, I'm pretty sure it's the switch in the rad. Good news: unscrew and replace and it is a cheap fix.

9 4 4 E n g i n e / C o o l i n g 19


REMOVING AND INSTALLING RADIATOR

R e m o v i n g
1. Unscrew cap on expansion tank. If engine is hot, first turn cap to first catch and let pressure escape. Then unscrew cap completely.
2. Remove air cleaner complete with air flow sensor.
3. Remove splash guard.
4. Drain and catch coolant through drain plug opening on radiator or coolant hose.
5. Disconnect wire harness on fan housing.
6. Unscrew three each bolts on top and bottom and remove complete fan housing.
7. Disconnect coolant hoses.
8. Cars with automatic transmission: Disconnect ATF hoses on radiator while holding.
9. Loosen two straps on coolant feed hose and two clamps.
10. Disconnect vent hose, tilting radiator back slightly for this purpose.
11. Remove radiator from below.

I n s t a l l i n g
1. Check that radiator fits properly in rubber mounts. Place radiator on bottom rubber mounts first and then press in forward direction, making sure that rubber seal between top of radiator and jack carrier is not damaged.
2. Install clamps and straps.
3. Pour in coolant and bleed cooling system (see page 19 -1).

REMOVING AND INSTALLING TEMPERATURE SWITCH
Removing
1. Remove air cleaner complete with air flow sensor.
2. Remove splash guard.
3. Remove fan housing.
4. Drain approx. 2 liters of coolant.
5. Unscrew temperature switch (wrench size across flats: 30 mm).

Installing
Torques:
- with plastic thread: 20 Nm
- with brass thread: 28 Nm
each in conjunction with a new fiber
seal ring, Part No. 900.123.012.70

CHECKING TEMPERATURE SWITCH
1. Remove temperature switch.
2. Connect testing buller on flat male plugs of switch. Place switch in warm water bath. Buzzer must sound off at temperature of about 92°C and stop buzzing when temperature drops to approx. 87°C.

[smkn951]

thanks everyone. i just want a quick fix to drive the car to my house about 6 miles, r/s fan doesnot turn on and it over heats about 20 minutes of normal operation. just don't want to take the chace of screwing something up. i'm getting the car for 1200, i think it's better to safe than replace a major component.

[AKCJ]

Just a note - if you're driving at over 40 mph or 50 mph you're getting plenty of air through the radiator and the electric fans don't run. Just saying you can run without the fans in the short term (I ran without mine for several years . . .).

[smkn951]

i think the max speed limit is 34 in the area plus the temp today will be in the 90s in el paso tx..

[Dr944S2]

Hi,

the video shows how to replace the switch:

Thermoschalter Porsche 944 S2 - YouTube

If you are fast, you will not loose more than 1 l of cooling liquid.

Best regards,

Jürgen

[Rasta Monsta]

+1, if it overheats while rolling there is another problem.