Overheating- fan question

[thamlin000]

For the past week, my 83 944 5-spd has run hot. Temperature gauge reads 2/3+ in traffic and at idle and will cool to the 1/2 mark only at high speeds on the freeway. I've driven this car since 1996, and it has never strayed past the 1/2 mark on the temp gauge and normally stays at the 1/3 mark. Coolant level is fine and the water pump was replaced 5 years ago.

Although I hear the fan motor running I only see one fan spinning. Aren't both fans supposed to run, especially when the engine is very hot? Is this the reason my car overheats in traffic but not on the freeway? Could the fix be as easy as a new fan switch?

Any help is appreciated.

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83 944

[Andre]

I have a late model but in mine both fans run. I dont think it is the fan switch though because there is just one and if it was faulty i dont think either of the fans would run.

But just to let you know dont take my word for it, i am totally new to these cars, or any cars for that matter.

[jseel]

both fans should be spinning when the ignition is on, only one when the car is shut off. the plug on the one fan may be loose, or maybe a bad thermoswitch(fan switch). pull the plug halfway off and short out the terminals with the ignition on.both fans should come on. may also be the fan motor broke. watch your fingers! hope this helps! oh yea the lower temp thermostat never hurts...its easy to find

[CrazySOB]

I have an "84" and only 1 fan turns on to cool it. Then when I turn on the ac the other fan turns on too and both fans run. That's how mine works (don't know if it's right nether the less that's the way it works). hope this helps some.

Steve

[Lawrence Coppari]

My '86 944T was doing that. A new water pump and thermostats fixed it. But this is only a possibility.

See if you have air in your system. That is the easiest thing to check besides fan wires.

You could hot wire the fan that is not coming on to see if it is functional.

I'm assuming your car is similar to mine. I have been wrong before basing what I say on the assumption that the 944's are just like 944T's.

[This message has been edited by Lawrence Coppari (edited 07-21-2001).]

[eligunn]

Both fans run with the ignition on, and only one with it turned off. After you drive your car try shutting it off then turining the ignition back on and you'll see what i mean. Also those temperture guages are really fruity. Did you notice that it will jump up to 3/4 bar and then jump back down all the way to 1/4 bar once you are moving and then sometimes it will settle at the middle? Don't worry about it unless it gets into the red. And if you don't trust your guage you will know if it's hot because when they get hot they spit coolant all over the place.

[SoCal Hobo]

Both fans should be running with or without the A/C on. Needs this extra "suction" to pull air through the additional A/C condencer "radiator" sandwiched in front of the regular radiator.

On my first "dead fan" I checked the fuses, each fan seems to have it's own on my fuse block, to find one blown. Replaced it and it blew again. Took out the dead fan to find that the front bearing was sized up. Seems that even though a new 944 83 cost over $35,000 at the time, Porcshe/Bosch could only put open cage ball bearings in their fans. Fans that see the brunt of all the nasty rain, snow and sleet we drive through. Dumb!

Soooo, I matched the bearings up with a local bearing supply house and replaced the open bearings with doubled sealed bearings on the new fan and in the other fan that was still working. differance in cost between the sealed and open was less than a dollar.

No problems after ten years.

Still would like a concise electrical schematic for the 83 so I can fix my windows. (see other thread)

[Ehab]

First, check to see if there is power going to the fan, unplug the wires, and test the voltage with a voltmeter (be careful with your hands around the fan area if the other fan is spinning as well). I would unplug both fans, and turn the AC on and test in a very short time (before the car overheats). If there is power in the plug (14 volts), then it is the fan itself.

If you can, try to either take out the fan assembley and test the fan to see if it is working, from what you describe it sounds like either the motor or the bearings could be a problem. Without taking the fan out, check the resistance across the fan motor, it should be on the order of a few ohms. If it is open (resistance is too high) you have a dead motor, if it is Zero, that also implies that the motor is melted and somehow shorting the circuit, but in that case, you probably blew the fuse and the voltage in the wire plug should be zero.

I had to replace mine a year ago, you can get a used one from ebay or something.


E