Getting ready to tackle cam adjuster seals - please help.

[Barty]

Getting ready to do cam adjuster seals on my wife's 99 A6 Avant. Couple of questions:

1. How do you guys rotate the crank to get the engine to TDC? There is no hardly any room to squeeze a breaker bar between the radiator fans and the crank pulley. Also, what kind of socket do I need for this task? Do I understand correctly that the markings on the crank pulley will line up when engine is at TDC and the cam marks also will allign?

2. I suspect that the infamous half-moon seal needs to be changed. Do I understand correctly I need to remove the intake cam a bit to gain access (losening the adjuster will not give enough clearance). If so I need to get the engine to TDC so I can allign the cams with the notches.

Thanks a lot for your help.

[Eric 2.7]

1) I believe the crank itself is a 12-point 25 mm (maybe 24 mm), but I used a 12-point 1" socket and it fit perfectly. Rotate only clockwise. You can see the mark on the plastic shroud and on the crank pulley which line up, but you really need to have the lock carrier (clip) in service position to do this. I also strongly recommend using both the crank lock tool and the camshaft locating bar. You cannot be even one tooth off.

2) I think the half moon part of the seal is the main problem anyway, so you'll have to go after that. The Bentley guide has you taking both cams out which is why you need to locate TDC in the first place, but:

I did my cam adjuster gaskets on both sides very successfully without disturbing the camshafts at all. The key is to get the mating surfaces totally clean which is tough when you can only lift the cam adjuster like 1/4". The benefit is much less time and risk because you don't mess with camshafts, timing belt or anything else.

If you needed more clearance, I think you could loosen only the intake cam (not directly driven by the timing belt) and not have to mess with the timing belt, crank or service position at all.

[Barty]

Man, it is people like yourself that make this forum awesome. 5 minutes and I have a very comprehensive answer! Thanks a lot Eric.

If I just compress the adjuster (I have the 3366 tool) will I have enough clearance to lift the half moon seal out of the way? Or do I need to loosen the intake cam a bit to gain more clearance, and if so can I do it without setting the engine at TDC.
I agree with you 100%. I think the half moon seal shrinks with heat or whataver and lets oil to seep through. I have seen pictures showing it shrunk considerably.
The reason that I hate to mess with TDC is like you say, I would have to put the front in the service position and that is a major pain in the butt (don't I have to remove the bumper to do that). I do not want to create more work than I have to. Also, I only have 1 day to do that job.

[Eric 2.7]

to slide out the metal gasket and the half moon rubber piece. I did not loosen the intake cam at all.

Doing it my way takes about 1.5 to 2 hours per side. I cant remember, but you might need to remove the driver side timing belt outer and inner cover. You'll be able to tell when you get there. You don't need to do service position to do that.

I used a bright light and many Q-tips to make sure I had the mating surfaces totally clean. I started with the Q's soaked in orange degreaser and ended with nothing on them to just dry the surfaces. I think if there is any oil on the surfaces, leaks will return sooner. Watch for the groove in the head which receives the outer flange of the rubber half moon. If you can get everything clean, I don't think there is anything wrong with this method.

The other thing you'll want to look into is the suction jet pump (pretty sure your car has one) which has been identified as the root of this problem. It plugs which pressurizes the crankcase and upper valve train which causes oil to find the weak spot (the cam adjuster gaskets). There are a couple of pictures of the thing in my picture poster with location on a 2.7. It's prolly slightly different on your engine. You'll want to replace this for sure. It should only cost like $20.

Good luck!

[Barty]

Eric,
Understand and thanks again! I had the pump replaced as a part of a recall. They replaced that black pump and a green one (some sort of valve) so I should be OK. I checked for the breather hoses and they seem OK (i.e. they seem not to be plugged). I will post back after I complete the repair.
I often notice that stuff in the Bentley etc. is not the most efficient way of doing things. You method seems very straightforward.

Bart

[JimR]

• here's a pretty good meta-post on it. Nice job on your post, bookmarked. In fact, I think I'll add this thread to the meta-post.

[6ULDV8]

to do the job right the first time. My point is that if the adjuster gaskets are leaking then the cam seals are also leaking or are very soon to be leaking. So why not do the job right the first time and be done with it. That means pulling the cams and replacing everything. If you were paying somebody like the dealer to do the job, which way would you have them do it?