ploglet

I am looking for any input on the possible problems with a 1991 964 C4. I am looking at buying one and wanted to know more about the distributor problem and the dual mass flywheel issue. Is there anyway to know if the flywheel problem has been fixed? The car I am looking at is a 1991 964C4 with 84K on the clock. I would think that if the car has 84K on it, the flywheel problem would have raised its head and would have been fixed. But...
Thanks for any information.

Randall G.

Hello Ploglet,

The only way I am aware of to verify the dual mass flywheel has been upgraded--short of taking apart the transmission and looking for the LUK stamp on the flywheel--is a receipt showing the flywheel has been replaced (with the proper part #).

If the current owner is unable to demonstrate that the DMF has been upgraded to the LUK, ask that he/she knock (at least) $1k off the price as insurance towards future DMF replacement. A new DMF is around $800, a full clutch job with DMF should run from $2000 to $2800, depending on who does the work.

You've probably already figured this out, but the installation of a vent kit is much easier to verify. You can find a picture of an installed vent kit at the end of recently updated thread "Tales of Woe--No Compression."

Good luck!

ploglet

Randall, thanks for the information. I asked the fellow as to whether or not the DMF had been changed and he was not sure. I will use that I guess in bartering a price for the car. Would it seem possible that a car could have 84K on it and still be using the DMF? I would have thought that the DMF would have come apart by then. Any ideas?

horst

That is unlikely, but certainly possible.

ploglet

What exactly were the problems with the DMF? Any ideas where I can buy a vent kit for the distributor?

Randall G.

Hi Ploglet,

When my DMF failed, it manifested itself as drive-line vibration, especially when climbing a grade in too high a gear (i.e., lugging the engine). I've heard of others that have actually had the DMF self-destruct (loose debris).

The replacement LUK DMF has proven to be quite robust. Besides being used in the 964, it was also used in the 993. I just recently heard of a failed LUK for the first time. I've also heard of one that showed signs of going bad. The owner was installing a lightweight flywheel, and just trashed the old DMF. These are the only failed/failing LUKs I personally have knowledge of.

Curious ... does the current owner know when the clutch was replaced last, if ever?

Unless the current owner knows the history of the distributor belt, you're going to want to have its condition checked. Or, better yet, you'll want to just have the belt replaced. Mine failed at 73k miles, and that seems to be fairly typical.

If you can get the distributor out of the car--and can stand not being able to drive the car for a week or so--Steve Weiner of Rennsport will replace the belt and install the vent-kit for $150. A good deal, and you know it was done correctly.

If you want to install the kit yourself, Pelican Parts sells them for $13.90:


http://www.pelicanparts.com/

Best of luck!

ploglet

Randall,
Thanks again. Seems like you are the man with the information. I will ask about the clutch. The current owner has had the car for about 4 years and 30K miles. To the best of my knowledge he has not had the clutch replaced during his ownership. Although I cannot say for sure whether the previous owner had the clutch replaced while he owned it. If the clutch has been replaced do you think they would have gone ahead and done the replacement of the DMF? I live in Colorado and drove the car up one of the mountain passes today and the car did not sudder at all. It seems very well kept. I have owned an 89' C4 prior to this one, although I knew the DMF had been replaced.
I will ask the owner of the car about the clutch replacement and then try and make the decision. Thanks for the info about Steve Weiner and the distributor replacement. Thnaks.

Randall G.

Yes, they should have installed the LUK, but you never know. Could have had a PO that was really trying to cut corners, and reinstalled the Fruedenberg (old style) DMF.

FWIW, I do believe '89 C4s did not use a DMF. You might call it an advantage of the model year .

Hope the car continues to pan out!

Bill Wagner

Just a point I thought I would throw in on this thread. If anyone is going to replace their DMF, make SURE you check the parts supplier and make sure you are getting a LUK and NOT another Freudenberg. There's no point in replacing a functioning Freudenberg with another, newer Freudenberg...it just delays the potential problems.

Several of the web and mail based suppliers seem to be selling Freudenbergs.

Good Luck,

Bill Wagner

Adrian

Just to follow up on Bills comments which are very true. The C4 in the parts catalogue does not show the LUK part number. Only the Technical Service Bulletin shows the LUK approved for the C4. You have to do what Bill says, you have to "ASK" for the LUK.If you ask for what is in the parts catalogue you get the old one,
Ciao,
Adrian
911C4

Adrian

Oh yes. The 1989 C4 (K series) DID NOT HAVE A Dual Mass Flywheel. However I have heard recently of a couple of people trying to install them. Did not work out very well,
Ciao,
Adrian
911C4

Bill Gregory

Ploglet,

While on the topic of 1991 C4 problems, you probably know already that Porsche addressed the leaking cylinder head issue in 1991 at engine number 62M06836 by fitting new cylinders with seals. Prior to that, Porsche would effect a repair if there was leakage that was wet to the touch, not just showing stains of past leakage. At the time, this only affected a small percentage of 964's.

ploglet

Bill, thanks for the heads up on the cylinder numbers. This car does not leak any oil on the underside, which seems to be somewhat of a rarity after looking at a few others. The car runs very smoothly up the mountians that I took it up. No jerky and plenty of power. I had thought I wanted to get a C2 after owning a C4 but I think the versatility of the C4 is worth it out here in Colorado.
I know alot of you might not like to hear this but I drove my last C4 in the snow and it was an amazing car. Would go skiing in it all the time and felt completly secure. Not like some of the 4X4 trucks owners I saw on the roads!
Anything else anyone would recommend I look out for in this year or model?

JonSeigel

Ploglet:
What did you use to carry your skis in your C4? Yakima? Thule? Someone else's gizmo?

Thanks

Bill Gregory

Actually, I believe that Bruce Anderson has said that the original C4 has some unique handling characteristics that some don't like (perhaps as compared to the 993-based C4), however that they do excel at driving in the snow.