3.6 leaking oil? Head gasket upgrade? Options?

FirstGen · 10-20-2006, 12:42 PM

I know this isn't the 964 section however I figured I would get a better responce over here...

I recently bought a 1990 964 C2 with the 3.6. It has a severe oil leak. I am told it is because the head gasket update was never done. What options do I have besides spending another 6-10 grand on a rebuild?

Thanks for your time...

JB36 · 10-20-2006, 02:02 PM

I'm not an expert, so feel free to correct me:

I don't think you have a lot of options. You'll need new cylinders and the heads machined for the gaskets to fix it properly. I was also told you can no longer buy just the cylinders, but the cylinders and pistons as a set. I rejected a 964 when a PPI reveled a similar problem

Bill Verburg · Bill Verburg's Garage

Ingo Schmitz did a nice write up on his, here and here

Jeff Alton · 10-20-2006, 04:33 PM

Steve W at Rennsport Systems can have your original cylinders machined to take a 993 head sealing ring. (assumming they are in serviceable condition) He did a set for me (pretty inexpensive too) and they worked great. I think they have been doing this for years. I did not read the "ingo" threads again, but he may have done something similar.

Cheers

john walker's workshop · 10-20-2006, 05:12 PM

severe oil leaks are usually something other than the head to cylinder issue. you get more of a light seepage there. case through bolt o rings, oil return tube seals, chain housing and valve cover gaskets, external oil lines, and various other things tend to leak lots more. the only dry 964 engine is one that has been taken completely apart and properly rebuilt/resealed. you rarely get away with doing a partial job, expecting to end up with a dry engine.

FirstGen · 10-20-2006, 07:19 PM

Thank you guys...

Steve@Rennsport · 10-20-2006, 07:36 PM

As Jeff said, we've had success machining these cylinders & heads to accept the 993 head gaskets and putting a slight bevel into the tops of the cylinders to help "bite" into the gasket.

We have 20+ sets of these on the road for several years now with nary a leak from the head-cylinder junction.

Naturally, this assumes that the cylinders are in perfect shape since Mahle doesn't sell pistons or cylinders separately; only in matched sets.

If one's pistons & cylinders are in good condition with having only oil leak issues, this is an effective and cost-saving repair. As John W. said, these engines tend to leak from many places (due to to high running temps) so all those other places he mentioned need to be addressed at the same time. We use premium gasket kits that are better than OEM ones that helps keep these motors dry for longer periods of time.

Jeff Alton · 11-01-2006, 08:01 PM

What John says I agree with 100%. The motor that had Steve's machining done is nice and dry. I also used a Wrightwood gasket set with it. If you are into it deep enough to have the P/C set off, might as well split the case and finish the job.

Cheers

dewflex · 01-25-2007, 05:16 AM

Anyone have a ball park price to fix? Mine is doing it to and my mechanic wants to do an entire rebuild, very expensive! I understand that the factory fix is new pistons and cylinders.

bazar01 · bazar01's Garage

Everything will be guess work until you clean the engine up and trace the source of the oil leaks.
PPI did not discover the oil leaks or you just took a chance?

You may be lucky it could be as simple as leak from the power steering camshaft drive seal and o-ring,
oil return fitting crush washer, oil pressure sensor mount o-ring, or chain tensioner oil supply bridge o-rings.

Worst case will be the ones already mentioned above and may need machining wok.

Good luck.

dewflex · 01-25-2007, 10:58 AM

I have had my car 8 or 9 years now. When I bought it, I didn't know anything about the car or its problems. My mechanic has done quite a few of the top end fixes, only to have a seal leak on the bottom end when the customer didn't want to do the total overhaul. I'm not opposed to doing it all, I just can't afford it! It's not the oil dripping that bothers me so much, it just has gotten to the point on my car that it is seeping into the heat exchangers which smells up the cabin.

I took these today. Basically, I can keep fixing the small stuff and it probably won't help, or dive in and rebuild. With only 80,000, I'm not ready to rebuild yet.