C5 S6: Replacing real cam seal

[Bcsangerman]

I replaced all my cam seals and plugs last year, however, the drivers side real seal (not plug), is leaking.

I ordered another replacement, but to swap it, can I just remove the sensor or do I need to set and lock TDC?

Thanks

[seizedfunds]

I replaced all my cam seals and plugs last year, however, the drivers side real seal (not plug), is leaking.

I ordered another replacement, but to swap it, can I just remove the sensor or do I need to set and lock TDC?

Thanks

Is it under a cam sensor? You're good.
Is it under a gear? Not so good.

[Calif_Kid]

I've only worked on 2.7T engines, but is the leak you are having coming from the camshaft positioning sensor on the rear of the driver side intake camshaft? If so, then I believe you can just pull off the cam positioning sensor cover and change out the seal.

When I changed the valve cover gaskets and cam chain tensioner shoes on my 2001 A6 2.7T, after I got everything together, the engine started fine and I thought everything was OK, but after a few minutes, I had a pretty fast oil drip from the rear driver side. I checked, and I saw oil coming from the cam positioning sensor, and it turns out that I had pressed the seal where the camshaft positioning sensor is with my fingers, but it wasn't in quite enough, so I used a round spacer etc., and pulled it fully in place with a bolt.

- Jim

[danspach]

Here’s an idea of what you’re looking at. Easier to understand when the cal PE cover isn’t in the way though I realize you’ll be keeping yours in place.

It’s snug back there but once the cam position sensor is out the seal is next in line if you can get a puller in there.






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[Bcsangerman]

Thanks for confirming.

I’ve got the valve cover off, and just received the new seal.

Hopefully I can make the swap with the limited space.

[Bcsangerman]

Any thoughts on why a brand new seal leaked? Want to make sure I don’t make the same mistake.

[ShelbyM3]

These seals just fail. All of them. Some as quickly as 10,000 miles. I think it’s just the nature of the beast. In your case, it was probably not seated all the way or there may have been some debris or carbon in the sealing area. If you look at the pictures above from @danspach, you can see a wear mark on the camshaft where the seal seats. That could be your culprit, too. Also, camshaft cap back there also uses RTV to seal, as an fyi.

Prep the daylights out of it and finish with some acetone or something to really clean the surface of any solvents used, too. Clean the camshaft off where the seal seats. Take a little piece of abrasive fine grit something like 0000 Steele wool and WD-40 to scrub it, being sure to not get anything in the cylinder heads. Spray the Steele wool not the camshaft. Clean out both sides of the camshaft caps really well. And, if you want a 100% solid seal you could always use RTV, but I’m not a big fan of that. My personal opinion. I’ve pulled apart a handful of 2.7’s with RTV and it always ends up inside the cylinder head and is just a pain to clean.

If you did all of this already, try try again. I’ve heard of folks using wood screws to thread into the seal and pop it out using a small pry bar. Not sure if you’ll have the room for that. You may find it easier to pull the camshaft cap and deal with it that way if your valve cover is off.


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[Calif_Kid]

At the top of this thread, you mentioned that you replaced the seals a year ago, so it wasn't really new was it? For me, the leak/drip was quite fast, but was fine when I installed a new seal and made sure it was fully seated by pulling it fully seated with the bolt plus spacer.

If I remember correctly, when I had the leak/drip from that seal, I looked for a new seal, and I think that some have a teflon seal without a spring, while others had rubber for the seal with a spring. I think that the new seal I installed had the rubber with the spring. Looking at ECS tuning for those seals, they don't go into much detail, but I think that there are a teflon based seal plus a rubber based one with a spring. The leak/drip that I had was quite fast, so maybe you had a different issue than I did. What ShelbyM3 suggested above (posted just before my post) sounds good to me.

- Jim

[danspach]

Any thoughts on why a brand new seal leaked? Want to make sure I don’t make the same mistake.

It’ll be a LOT easier with the valve cover off.


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[Bcsangerman]

Thanks. Seal is actually two years old now from the time I replaced it, but it’s only got 300-400 miles on it. (Car does not get driven), and it’s been leaking for over a year now (haven’t had time to spend on it)

I’m going to see what I can do with the cam in place, but seems like it might be a good idea to pull the camshaft out to ensure the whole area is clean and clear.

[Avantly]

Try to get the seal slightly outboard of where it was originally. I.e. don't push it all the way against the inside shoulder as hard as you can... Push it in with a socket that bottoms out against the outer shoulder first if that makes any sense. The seal contact area becomes polished. Polished surfaces cannot carry any lubricating oil which results in accelerated seal wear. You could fix this with some emery cloth but I wouldn't try emery cloth without removing the cam, too much risk of contamination. This is the same reason that I use green scotchbrite on aluminum accumulator and solenoid bores in transmissions. The seal polishes the surface, you rebuild without fixing that surface and you may have immediate driveability complaints related to that accumulator or solenoid. Need to be within the ballpark of OEM surface roughness for OEM performance/longevity.