Anir

Greg and I spent some time troubleshooting my high oil temp problem today and would like some input. Basically, it likes to run between 9:00 and 10:00 lately (i.e. 221 and 248 F). Here's the data (thanks for the head start and excellent write-ups, Randall & EJ!):

- The air conditioning runs great with either its own relay or the identical oil cooler relay, so both relays seem fine.

- In the relay box, jumpering 30 and 87 does cause the fan to run on high

- However, jumpering 30 and 87c does not turn on the fan at slow speed

- Using EJ's trick of disconnecting the cable behind the right headlight assembly does not cause the fan to run on high as expected.

That's as far as Sherlock and I have gotten. Our guess is that the resistor is bad, and I am considering replacing the temperature sensor while I'm in the neighborhood.

Any thoughts or suggestions? Will I still have to remove the front bumper, or can I get to both parts from the right front wheelwell using Jai's tip of removing the bolt inside the right headlight housing to allow the cooler to slide out?

If I am forced to remove the bumper, should I consider adding the Turbo S cooler since the car does see track time?

Thanks in advance for tolerating all the questions!

Anir

Kim,

Thanks for the reply. We didn't have a voltmeter/ammeter (mine broke recently), so that's why we didn't continue with Randall's excellent diagnostic algorithm.

Randall G.

Hi Anir,

Sounds like you have two problems.

First, the resistor. Kim is right, try to verify with a multimeter, but a fan that doesn't jump in slow-speed (given that it jumps in fast) almost certainly = failed resistor.

Second, your fan should have started in fast-speed when you unplugged the sensor. There is a delay (~ one minute?) after you unplug the sensor before the fan starts in fast-speed. Did you wait very long before plugging the sensor back in? Also, the ignition must be on for the fan to run. If this doesn't work for you, either:

-the fast-speed contact on the relay is bad.
-The $CCU$ is not sending a signal to start the fan in fast-speed after the sensor is disconnected.

Best of luck!

rcwelch

Anir...I am right in the middle of my oil fan operation and got the same results that you did. I then did the voltmeter per Randall and confirmed in my mind that it was the resistor. Just to make sure I took my car to the local dealer and a mechanic that I have made friends with and the service manager listened to my story as to what I had done with the exception I didn't tell them about my results with the voltmeter. They both confirmed my belief that the resistor is bad...They said mine was not the only one they have seen with the symptons and replacing the resistor was the cure. Hope this helps but it sounds like your resistor is the problem.

rcwelch
1995 993 Coupe

Greg Fishman

[quote]Originally posted by Randall G.:
<strong>Second, your fan should have started in fast-speed when you unplugged the sensor. There is a delay (~ one minute?) after you unplug the sensor before the fan starts in fast-speed. Did you wait very long before plugging the sensor back in? Also, the ignition must be on for the fan to run. If this doesn't work for you, either:

-the fast-speed contact on the relay is bad.
-The $CCU$ is not sending a signal to start the fan in fast-speed after the sensor is disconnected.

Best of luck!</strong><hr></blockquote>

Randall,
We unplugged the sensor and it never came on. I don't remember if we had the relay in or not. Would it run either way. Anir, if not go put the relay back in and it should start up, we left the sensor disconnected.
Greg

Anir

Randall, Kim, RC -

Thanks for the quick response and helpful suggestions. Greg might be right about forgetting to reinstall the relay prior to testing the disconnect. I'll check again tomorrow.

I've sent an e-mail to Phil Anderson at Suncoast (an "official Rennlist sponsor" ) to order the resistor (993.616.521.01) and temperature sensor (964.624.110.00). I'm considering replacing similar air conditioning components during the requisite bumper "surgery". Which AC components should I order? Are the resistors the same, like the relays?

Anybody want to sell a used Turbo S cooler kit? Martin? Carl? It seems like a good time to upgrade.

Randall G.

Hi Anir, Greg,

Yes, the fan won't start after disconnecting the sensor if the relay is removed. Hopefully, that's the case .

Anir ... you might want to drive about for awhile with the fan running continuously in fast speed before jumping into an additional cooler. The fast speed fan is amazingly effective--at least it is on a N/A car, street use. You could install a switch to run the fan in fast-speed in lieu of the extra cooler. Maybe try the fast-speed fan switch on a hot & hard track day before springing for the aux. cooler?

c4-toy

I Ordered and received my 2 low speed fan resistors about 2 weeks ago. Got them from Hendrick porsche in NC. Cost me $66 for 2 of them (1 for oil cooler, 1 for a/c) including shipping. Part guy quoted me $44.00 1st before i balked and told him Sunset Porche priced them at $30. He matched the price.
Now i need to get enough nerve to remove my front bumper and do the work. Is this dificult to do? I am a novice mechanic. Any tips?
Thx Joe b 96 C4 Cab.

E. J. - 993 Alumni

Anir,

Did you ever get the fan to come on high with the plug undone?

If not try to restart the car a few times - it should work, especially with the jumper working on high.

E. J.