C H

I couldn't find what I needed using the search so hopefully someone knows. At what position on the gauge does the oil cooler fan turn on? I jumped the relay and the fan works, but I got the gauge just under half way up and still no fan. I assume there is a high and a low speed mark since the relay has 2 settings. Also what is the sensor on the top of the oil cooler for?

Thanks
Curtis

DarrylH

Everything you ever wanted to know about the system is here: http://p-car.com/diy/fan/

C H

Thanks for the quick reply. Here is the answer to my question.

At 87c/188F for a 964, 83c/181F for a 993 (per manual), the oil cooler thermostat opens and oil starts to flow to the cooler.

At 212For 230F (993), the thermosender—via the control unit—starts the oil cooler fan in slow speed.
At 239F (964), the oil cooler fan switches to fast speed.

jeff522

There was a thread not to long ago about how bad are short trips.There was concern about water build up in the oil from not getting the temp up enought to boil off the water.Most who responded felt that so long as the oil thermostat opens that water condensation should not be a problem.I hate to bring facts into the discustion,but if the thermostat opens at 87C/188F that is well below the boiling point of water.(That is unless you are at 25,000 Ft elavation.)It may need even a higher temp depending on how much pressure the system is under. So at what point dose the water boil off at relative to the oil temp gauge.

Lew964

Curtis, When you switch your engine off when its hot do any fans on your car still run until its cooled down. Just wondered as mine don't.
By the way, my oil temp guage never goes above the 8 o'clock position.

Indycam

When the oil hits the back side of the piston and or cylinder wall and the piston is well over 212 , I'm guessing the oil get cooked past 212 . Any water gets flash boiled and gets out of the oil as super heated steam .

"if the thermostat opens at 87C/188F that is well below the boiling point of water"
If it opens at 188 and the oil temp goes up to 245 ?

DarrylH

With the key off, the auxiliary cooling function of the rear blower only kicks in on shutdown if the car is VERY hot. The temperature has to be ~90C. It would be very rare that this will happen with normal driving.

On hot summer day, >30C, stuck in a tailback, idling, inching along, you'll likely see your temp gauge register higher, more like 9 or 9:30 ish. Then the oil cooler fan starts and brings it back down...and you may also hear the rear blower run to dump some heat (the threshold temp with the key on is much lower.)

jeff522

Thanks Indycam

C H

Still haven't got the car hot enough for the fan to come on. Just found out that the bearing must be partially seized. Comes on ok on high mode and continues running when switched to low, but the bearings have enough resistance that when the fan is stopped it doesn't come on without a little help.

Anyone ever take the fan apart and clean/grease the bearings? Did this with the power seat motors and they now work great.

Lew964

Thanks Darryl, rare we have those temps over here in the UK.

QUOTE=DarrylH]With the key off, the auxiliary cooling function of the rear blower only kicks in on shutdown if the car is VERY hot. The temperature has to be ~90C. It would be very rare that this will happen with normal driving.

On hot summer day, >30C, stuck in a tailback, idling, inching along, you'll likely see your temp gauge register higher, more like 9 or 9:30 ish. Then the oil cooler fan starts and brings it back down...and you may also hear the rear blower run to dump some heat (the threshold temp with the key on is much lower.)[/QUOTE]