changeover to head gasket

[a3holerman]

Hi,

Well here is another question for you all. Can someone tell me with what engine serial number the 3.6 engine had head gaskets ? I am under the impression that some time in 1991 the factory used head gaskets.

Thanks

Tom

[Bill Wagner]

Hi Tom:

Most of the '91 cars will have the head gasket update. My car was built in January of 1991 and it has the updates, and by then Porsche was several thousand units into production.

The serial numbers for the engine change over is:

62 M 06836, M64.01 for manual transmission
62 M 52757, M64.02 for Tiptronic transmissions

Any car with one of the serial numbers above or before will not have the cylinder head gaskets installed.

The cylinder head problem for cars without the gaskets installed is GROSSLY overblown. If it's going to rear it's ugly head, it usually doesn't do it until the car has high mileage (100K miles or more...but it CAN obviously happen earlier). More common leaks will occur with the oil lines, valve cover gaskets, tensioner gaskets, etc. than will occur with the cylinder head.

Good Luck,

Bill Wagner

[a3holerman]

Bill,

Thank you very much for the reply. I feel a bit better now. I wll look at the engine serial number and see for sure.

Thanks again

Tom

[Roland Kunz]

Hello

Just called Porsche factory spare sales dept. ( Siegele ):

The first engines with gasket came in MY 91

On M 64.01 the spliit is # 62 M 06837

On M 64.02 the spliit is # 62 M 52758

[Bill Wagner]

Roland:

Just an FYI. I added another sentence to my post to clarify the difference in serial numbers (by 1) between your post and mine.

CHEERS

Bill Wagner

[Roland Kunz]

Hello

Sorry Bill didn´t meant that way I just needed some time to verify the stuff and i work offline. I don´t reload threads before posts to see what happend inbetween.
In germany many cars where retrofitet so you never can go for sure.

Grüsse

[Bill Wagner]

No big deal, Roland. The point needed a little clarification anyway.

CHEERS

Bill Wagner

[Britwrench]

The cylinder to head leak is fairly common and can affect cars with low and high miles. It seems to depend on climate, maintnenance and if the undertray is fitted.

More common is leakge from the cylinder base o-rings and crankcase through bolts.
We machine the cylinder heads and cylinders for early cars.
This cures the cylinder leakage problem if the customer doesn't want to renew the pistons and cylinders.

If you are looking at an early 964 and the rest of it checks out
good, at the right price they can be a good buy.

[JonSeigel]

Hey Britwrench:

Even though I have a '93 and don't have to worry about this problem, I am curious: for those without gaskets, what does having the undertray on or off have to do with it?

Thanks.

[Britwrench]

It depends on the ambient temperature where you live, but leaving the undertray on makes the engine run hot and that bakes all the seals and gaskets, which lead to...leaks.

93 MY may not have the head gasket problems, but they are not immune from the timing cover seal leakage. The later cars do seem to be noticeably more reliable.

[Bill Wagner]

Britwrench:

When you say the leaks are "fairly" common, could you put that in terms of a percentage. A survey at the SmartGroups.com website indicated the frequency was low, but I suppose it could be a problem with semantics. For me, low would be 10% or less, and common would be 50%.

Could you clarify your answer in terms of percentages??

Thanks,

Bill Wagner

[Britwrench]

Hey Bill,

I couldn't really provide percentages, but it is sufficient that many shops have menu prices for the cylinder head/o-ring/timing cover leak repair. Having worked on 964s since their introduction I would have to guess that of the cars bought in for service cylinder head joint leakage in early cars is apparent on more than 20%. It obviously depends on the definition of "leak" . I never really noted any figures. Porsche obviously thought is was a problem as they updated the sealing method. In the last two weeks we repaired a 1990 C2 with 24,000 miles and a 1998 993
with 20,000 miles both with timing cover and base gasket leaks and from talking to other shops we aren't the only ones.
Most of the leaks seem to start in the 50,000 mile region, usually with timing cover and power steering drive seal leaks.


I really don't think it makes the car any less reliable than many other vehicles in the same class and the 993 is still the best
911 ever and the 964RS (euro) is a great sports car.

[Bill Wagner]

Thanks, BritWrench.

On the SmartGroups.com (a U.K. site) a survey was done and the figure we came up with was about 15% for the cylinder problem, so your educated guess of about 20% appears to be on target (beats the Hell out of 99%)

CHEERS,

Bill Wagner