928 GT R

It has become clear that all of us will need to Replace our head gaskets, and it is established that we should do so Before our Heads Become Swiss Cheese! Head gaskets are maintenance items with a lifecycle that is directly related to coolant system maintenance with lifespans as short as ten years while others have lasted over thirty years. All will require replacement eventually.

This thread is dedicated to being the comprehensive source for 928 head gasket replacement techniques, parts sources, tool suppliers and coolant system related issues.

Parts suppliers can post comprehensive parts lists and "Head Gasket" packages for each engine group.

Tool lists can be created and where to get hard to find items (like engine stand adaptors) or even "for rent" or difficult to manage "loaner tool sets" created.

Critical "While You Are In There" issues and suggestions can be addressed as well with the goal to help us become more efficient in our approach to long term ownership and maintenance.

Detailed video guides and disassembly/re-assembly sequences can be compiled, so those of us without access to qualified engine builders or budgets to send our cars across country can address this responsibly. These guides should be created so moderately skilled individuals can rationally approach, plan for, and succeed in performing our own head gasket replacements.

Advance thanks are extended for those individuals that take the time to make this a straightforward Go To Guide for this essential maintenance procedure that can be intimidating enough to kill cars and drive owners away from 928 ownership.



Moderator, I did do a search for this topic without success. If this topic has a comprehensive thread please delete this post.

Otherwise, have at it!

Bertrand Daoust

Thanks Dave for starting this thread.

I, like many of us as you mentioned, will need to do this job in the future.
As I have no experience at all in this kind of job, this thread will hopefully be my guide line when the time will come to do this.

Rennlist and all it's valuable members and vendors are the main reason why I can own such a car.
I'm sure this thread will be very useful for many of us.

Thanks again Dave for starting this thread and many, many thanks to all who will contribute.

Pasquo Wrencher

Very timely topic. I spent the weekend cleaning up my heads on my '81, and found the beginnings of the "Swiss cheese" corrosion. It appears to be just outside the head gasket metal sealing ring, but just barely. All the dark areas on the head appear to be corrosion, and have eaten into the metal. The area on the lower right is the worst.

Ad0911

How serious is this?

The Forgotten On

It can be minor enough to just need the heads skimmed by a machine shop, serious enough to require the heads being replaced, or somewhere in between.

They're made from a much softer aluminum than the block as corrode very easily if the proper coolant isn't used and replaced at correct service intervals.

But even still the blocks aren't impervious to corrosion either. My thread as an example https://rennlist.com/forums/928-foru...-on-928-a.html

The Porsche head gaskets are just repackaged VR gaskets BTW.

polecat702

I've done a bunch of S & BB Chevy engines plus Fords. Never done a 32 valve engine in my life. Plus at least 100 Harley Engines from every time period. I've got every tool a professional shop has except a tire changing machine. I have a lift, cherry picker, 3 stage trans jack, etc. I'll need to know how to reinstall the cams. I'll be taking my heads to Doc Brown, for refurbishing. Also do the top end refresh at the same time, along with TB/WP, cause I don't want to have to mess with this again for a while.

polecat702

Blake, were you able to use that repaired engine block?

drooman

We should separate out the techniques... 16v engine in, 32v engine in, and engines out.

Kevin in Atlanta

Maybe we should agree that no matter what, the task should start with the engine out. If it's time to replace the head gaskets, it's time for a lot other items to be replaced.

Chris Lockhart

I agree Kevin. IMHO the engine should come out as step one of the actual work.

A lot of pre planning should happen before you even touch the car. What else are you planning to do along with the head gaskets? Parts purchase for said list. I would hold off on head gasket selection until after you get the heads back from the machine shop. Gasket thickness will depend on the amount of material removed. Proper tools to do the job including specialty tools for timing the cams, removing and installing the cams, timing belt tensioner, etc.. A reputable machine shop familiar with DOHC aluminum heads. A good quality engine stand and engine hoist, the proper hardware or adaptor to mount the engine to the stand. It's also a good time to replace your engine wiring harness with one of Sean's or Carl's. Heck I forgot a lot of what I did throughout the process but I did find out that I had NOT done near enough planning. I believe the more you do, the smoother the whole process will go.

928 GT R

In general you do want to remove the engine! But I'm with drooman on this separation of techniques. The exception to removing the engine is relative to the condition of the bottom end of your cars engine and where you are in the maintenance cycle of the TB WP & Oil Pan & Motor Mounts.

On my XX8 car for example, the TB WP job is less than two years old and the Motor Mounts and oil pan gasket are fresh. That covers the major While You Are In There items. If a head gasket failed, I would simply do the top end in this case. My goal however, is to continue excellent maintenance of the cooling system and pull the motor on the next TB WP change and then combine the jobs with the motor out.

The problem with the Pull The Motor only scenario is that it can be such a big hit at one time that many enthusiasts will simply give up on the car and be forced to move on...

As Chris points out, Planning and Timing is everything when addressing head gaskets that have not failed but due to time should be replaced. My current thinking is that you want to synchronize at least your TB WP and Motor Mount jobs with the Head Gasket replacement if pulling the motor.

SeanR

Yep, I refuse to do head gaskets with the engine in the car. Do it right and do it once.

BRB-83-911SC

For quick reference, linked below is my head gasket saga. This is by no means a "how to" thread, but there may be some good info in there for those embarking on this journey.

https://rennlist.com/forums/928-foru...s-back-on.html

drooman

No matter what?

You can do head gaskets "right" in the car and there are plenty of realistic scenarios to do head gaskets in the car. Not everyone, in every situation, is in full on rebuild mode when they may need head gaskets. Real world limiting factors are time, money, etc. "Ideally" everyone would be pulling all of these engines and rebuilding them, but not everyone is "restoring" these cars, many people on here are just driving and maintaining them as required, and I don't think those readers should be eliminated from this discussion.

Carl Fausett

I agree. I think there is a place for head gasket replacement with engine in car. Especially 16v motors. Its pretty easy to do, and there are many owners who might want to DIY whereas if they have to pull the motor, they might not. Some are cautious not to over-spend on their early model 928, and a head gasket replacement (when needed) with engine in car is a relatively economical choice.