tgage

I'd been looking for a good excuse to spend the weekend locked in the garage.

I've been noticing the engine has been running a bit hot, and have traced the problem back to the oil cooler fan not turning on.

I suspect the ballast resistor for the oil cooler is bad... seems it happens a lot with age.... For that matter, the A/C condenser fan does not turn on either.... but since I never use it, I have not cared until now since I can't test the problem by comparison.

I tried testing the low fan speed (of the oil cooler) by removing relay R04 and jumpering 30 to 87c, however, nothing happens. High speed works by jumpering 30 to 87. Same with the A/C fan (no low speed, high is fine)

If the low speed fan does not come on when jumpering, does that mean the resistor is bad? (or am I on the wrong track?) I did the test with the ignition off.

Thanks,
tom

robbed666

Hi
Quick and dirty test, take a lead from the battery positive (preferably fused!, say 30Amps). Remove relay R04 and R14. Connect the lead to terminal 87c in turn on now vacant relay sockets (one at a time!). The fan motor for the oil cooler then then the A/c condenser should run low speed. If not the resistors or their associated wiring is open circuit.

HTH

OUR9II

Good tip. Tom, you may already know, but if not, there's more good info here, too.

http://p-car.com/diy/fan/

tgage

Thanks guys! I'm glad you mentioned the tidbit about using a testline with an inline fuse! How do I know, well, the first time I touched the battery, it popped it. So many thanks.

Yes, the fan did not turn on doing this test, so I ordered two new ballast resistors. Who knows, perhaps I'll use the A/C again (but 2X60 works fine.... two open windows at 60)

tom

dfinnegan

Thanks for the clarifacation on that. I was seriously thinking you meant open windws at 2x60!

tgage

I picked up two ballast resistors from the local Porsche dealership. My local mechanic kindly let me purchase them under his account, and the total cost was $89. I was very surprised!

Mike, I kindly thank you for sending me the p-car link as it was very helpful.

I decided to replace the A/C one first and read some prior posts that suggesed unbolting the condenser for better access, however, I was able to unscrew the bolt with patience. A small 4 mm allen wrench worked fine since there was no clearance for a socket.

I next replaced the oil cooler ballast resistor, and was stumped for a while thinking that it too used a hex bolt. My daughter came by after a few minutes and gave me an inspiration. "Hand over the gum in your mouth." I used the gum to see what kind of bolt was holding it on (I'm sure it was in a prior post, but I just missed that detail!). 10 mm. I suggested to my daughter that she could have her gum back but she left in disgust. So, that clued me in that the access was from below. I removed the lower guard and using a couple of flex extentions was able to remove it. Installing it back in was not too much trouble, but I did have to put something heavy on top the bolt so that I could thread the nut back on.

All went well. Everything works. While I was at it this evening, I decided that I'd switch over to R134a and was able to catch Jose at the shop so that he could evac the R12.

Again, thanks for the advice.

tom