Dan V

^ What Jean-Pierre said -- 'vraiment'. I'm not satisfied the oil is getting thru the cooler until I feel the heat on the fender with my own hand.

JasonF

Thanks Jean Pierre and Dan. I did notice that the fender was warm this morning after my 20 minute drive into work. So it appears that oil is getting to the cooler but the fan doesn't turn on to cool the oil. On my short drive to lunch today the temp did get above 9:30. The temperature did not automatically drop.

The plot thickens. I have also blown several (30 amp) oil cooler fuses (the No. 2 fuse). Could a faulty thermostat cause the fuse for the oil cooler to blow?

Finally, I don't hear that telltale "gurgling" of oil moving through the cooler that I used to hear on my old 993.

Thanks so much for your advice.

NP993

I've never heard a gurgling noise on my car, and actually I've never heard anyone with a 993 talk about this noise, or invoke it in diagnosing any problem whatsoever. So I would forget about gurgling noises and use far more empirical and reliable means for diagnosing what's wrong, such as what so many people have suggested in this thread.

I would also disregard the fender warmth test, as this too is unreliable (maybe your fender is warm because the car has been in the sun?). It's very, very easy to get a hand right next to the cooler to feel whether it's hot from oil circulation. Pop your right headlight out and put your hand over the cooler. Then you'll know for sure.

If you don't use precise and reliable means of diagnosing a problem, you're not going to find a solution. Gurgling noises and fender warmth are not high on the list of precision or reliability.

vjd3

Pull the passenger side headlight, and pull the electrical connector off the top of the cooler fan. The fan should operate constantly on the high speed. Drive the car, and see if that fixes your temperature problem.

I believe the thermostat is mechanical (it was on the 911SC and 3.2 Carrera, I doubt they changed it; they can be tested by being put into a pan of oil and heated, you will see it open when you get up around 180 degrees or so. They rarely fail.

I didn't mess with extra wiring or worrying about the resistors, I unplug the connector in the spring and plug it back in during the late fall. My temperature never gets above the first line.

JasonF

Thanks Vic. I did pull the connector last night and the fan did not come on. The fact that the No. 2 fuse keeps getting blown leads me to believe that maybe the fan motor itself is shot. Once the fuse went I couldn't get the fan to run at any speed.

vjd3

Sounds like that's your problem ... try DC Automotive and see if they have a preowned cooler fan.

JJJMCD

Guys - if you're having oil cooler fan issues, you may want to try replacing the relay itself.

Around three years ago, I noticed that my '91 C2 started to run hot (above 9:00pm), whereas it used to heat up to 9:00pm and then, once the oil cooler fan came on, cool back down to below 9:00pm. After reading the Rennlist posts on the topic, I told my mechanic to replace the ballast resistor, which he did and the problem was solved.

A few weeks ago, it started running hot again, so I brought it to my mechanic (a different one than before), thinking that the ballast resistor that had been replaced three years ago was shot. The mechanic, who is very familiar with air-cooled Porsches, jumpered the connection, determined that the ballast resistor and oil cooler fan itself were fine, and instead replaced the relay. The new relay did the trick and the oil cooler fan now comes on at 9:00pm like it used to do. The relay that he pulled out was dated 1990, so I guess it shouldn't be surprising that it was shot.

I mention all of this because the relay is infinitely easier to replace than the ballast resistor and may be the real culprit for some people.

Good luck!

Analog Theory

If your indie has a PST2 they should be able to test low and high speed fan operation. I had the same issue and found out within minutes that both my low and high speed fan resistors were shot without any additionl diag required. When we pulled the front bumper, it was clear by the look of the original parts that indeed, they were the culrprit.

See this link for an excellent overview of this issue http://p-car.com/diy/fan/ ultimately, my spent units looked exactly like the one on the left.....very common failure to the symptom you are experiencing.

- Jordan

ToreB

I can also confirm the defective resistor problem. The replacement kit comes with an additional cooling plate to avoid overheat again.

The most simple way to test if the resistor is defective is to pull out the fan relay, remove the square plastic cap, put the relay back in the fuse holder and then manually press the two relays inside. One of them should start the fan at low speed, the other high.
Changing the resistor is a bit fiddly, but I did it in 1/2 hour. Consider replacing both A/C and oil cooler resistors. Mine were both shot.
You can also test the A/C blower control in the same way as described above, just find the correct realy in the fuse box.

And by the way, there's only one resistor on each blower, reducing power and making it go slower. High blower setting is 12V directly to the blower motor.(no resistor in series)
Regards,
Tore

JasonF

Thanks for the advice, I will try to do the test with the relay. My first problem is that I keep blowing fuse number 2 ("oil cooler blower" per the fuse box lid) which renders every other diagnosis impossible.

I think the best approach is to replace the blower motor first to see if that is the cause of the fuse-blowing issue. (What else could it be, since that is the dedicated fuse to the blower itself?) If that's the case, then I'll probably replace the relay and resistor just to be certain. Thank god the weather is getting cooler, I can work on this for as long as it takes and not worry about getting stuck in traffic on a hot day!

Sweet993

I'm having the same issue as listed here. My fan doesn't seem to turn on in either high or low for the oil cooler or a/c. I've tried to test it via the jumper method using my volt meter but wasn't able to get either to turn on. If the resistor is completely shot will this prevent it turning on? I double checked the relay female sockets and believe I am doing it correctly but not sure what the probability of both fans not working.

Any advice?

schubee

Bringing up this old post...

The last couple weeks, I've been driving to UCLA from Irvine and I've noticed not so normal oil temps. I decided to check my oil cooler operation based on p-car.com.

I jumped the proper terminals and I'm only getting the fast speed to work. When I jump the slow speed terminals, nothing. Would this be a culprit of a failed resistor?

For my drive today, I'm going to unplug the connector to run the fan at fast speed continuously. Are there any issues running the fan at fast speed all the time? I'm aware that some do this while tracking their cars.

Thanks,
John

ToreB

High speed is better than nothing. Especially if you see that the oil temp rises above normal. You should check the low speed resitor on the condesner fan as well. See my DIY page for details on how to check the resistor and change it: http://www.bergvillfx.com/fanresistor.html
Cheers,
Tore

JB 911

"Paging Jason F paging Jason F"

you didn't finish the story! SO was it the fan ???resistors???? I'm guessing you may not even have the car now ... it's been a while....

nbuyabis

Hi Guys,

Resurrecting this thread.

Im having similar problems as Jason "has" been having.

I replaced the oil cooler balast resistor with a new one and jumpered R04 - No go

Jumpered R14 - Everything working - both Low/High fan speeds.

I did notice that the fuse #2 (30Amps) was blown. replaced it and still No go, infact it blew again!!

the fan doesn't turn on at any speed/temperature (to note, i have installed the over ride switch which worked beautifully until yesterday where the oil fan cooler stopped working

what to check next?

Thanks

Najeeb
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993 '95 Iris blue