I finally got around to replacing both my oil and AC fan ballast resistors today.

As always, things got off to a flying start with the AC side and I actually believed I would have the entire AC resistor job finished in 45 minutes.

That is... until I discovered that the bolt holding the old resistor on was so corroded that it wouldn't budge and I ended up chewing the inside of the allen head out, rather than moving the bolt.

To create some space I smashed the resistor (which was already cracked) and this successfully left the bolt standing alone. I have sprayed it with WD-40 but now that the head is chewed out, how can I remove this bolt? Forget dremelling - this bolt is very well tucked away!

For those who haven't witnessed the awkwardness of the position first hand, here are some photos borrowed from p-car.com:

 

I'm going to have to do that because my fan keeps shutting on and off like a yoyo..

 

Which fan? AC or oil cooler? If your bolt isn't stuck like mine, it really would be a 45 minute job (on the AC side anyway). I haven't tried the oil cooler side so I don't know whether that's easier or harder.

 

Well, I assisted on this DIY job a few weekends ago and it was no fun. I can assure you the right side is much worse than the a/c side. If you can get the bracket off that holds the oil cooler, then you'll be better off. But it it not easy to get to. I have this job coming up, but will wait until a/c weather returns.

 

Try leaving the old resistor in place and just disconnect the wiring. Mount the new resistor in a better location. That is what I did on the AC side of my 964. Don't fight a corroded bolt if you don't have to. Besides a new location may make it less susceptible to corrosion and easier to get at next time around.

 

Graham
That's exactly what I did on the oil cooler side. I disconnected the bad resistor at the "connection" shown on my pic in your post, connected the good one & mounted it using an existing hole into the trunk w/a bolt & nut, so no drilling was required & it's readily restored to oem if desired. The same process can be easily done on the ac side.
Dan

 

You are probably both right. Has anyone ever damaged anything by moving the mounting point?

Alan, the old resistor is completely gone already. I cracked it apart to leave just the bolt stuck in place.

 

Graham
My relocated oil resistor has been fine for the past 1+ yrs. Arguably, the new mount is better than oem. It's securely mounted in a more open area w/good airflow & away from the high heat of the oil (or ac) cooler. Plus, if replacement becomes necessary, it's an easy 5 min job once the fender liner is removed.

 

Dan, can you please post photos of your new mounting locations? This unseasonably warm weather may make this job necessary sooner rather than later. Thanks.

 

Rick
Sorry for the delayed response, but I've been buried at work trying to get my desk cleared for a long needed 2 week vacation.

I don't have any pictures for you. However, on my car there is a predrilled factory 3/16" (+/-) hole from the trunk into the fender located about 2" forward of the large rubber harness grommet which is now concealed by my Catz HID ballast. There are actually 2 holes, but I used the one closer to the front of the car. I think the holes are intended for use in mounting a Litronics ballast. The hole was covered by a small round car color painted paper sticker which I merely punctured. The hole could be felt through the sticker. I used that hole to insert a small bolt into the fender onto which I mounted the oil resistor secured by a nut. The resistor has a hex recess for the mounting & I used a nut sized for the hex opening so it wouldn't rotate. It was a nice, clean & easy relocation.

Other mounting spots may also work. The only tip is to be aware that the fender liner intrudes into the inside fender area so make sure the mounting point isn't going to interfere.

I'm sure this isn't a 1000 words, but I hope it substitutes for a picture.

 

A new reply to an ancient post. Thanks to the previous poster. I just replaced my oil cooler ballast resistor using the method above - via the pre-drillled unused hole. No drilling, no permanent modification. One hex bolt, a washer, two nuts (I double nutted it as you can't tighten the first one too much due to the resistor being fragile), dab of loctite. Done. Left the old one in place. If I'm sufficiently motivated I'll put it in the right place if the bumper comes off one day otherwise, it's going to be just fine where it is and I'll pay the extra few grammes weight penalty...:-)

 

Hi Guys: Did you replace both resistors without removing the front bumper cover?

 

yes, I just remove the headlight, grasp the set of wires that go to the resistor and pull. First you feel the plug come out of a clip, then as you continue to pull it comes unplugged.

Drill a mounting hole from the inside of trunk and mount the new resistor. Plug it in.
Done.

I like to mount it near the same location as the HID ballast but on the outside of the trunk, of course. This is a good, safe spot.

 

Thanks Mark. At the moment everything appears OK but it's nice to know how to get to these little items the easy way.

Mike

 

I bolted mine (AC side) to the underside of the tray that makes up the recess for the headlight bucket. That sucker gets hot and I wanted to keep it in a good air stream. 30 minute job