Cylinder head cover

[darek_u]

How this cover should be sealed to the head itself? Mine seems to be sealed with RTV or similar sealant and it is most likely passing oil. Not much, just enough to make the front of the head oily. Is it a big deal to remove it and re-seal? I can see that the camshaft cover will have to come off but this shouldn't be a big problem.

 

[gerryvz]

This front cylinder head timing chain cover uses the orange koala-claw MB anaerobic sealant, the same stuff as the intake cam solenoid mechanisms.

If the front covers are leaking, I would remove both of them, and re-seal them. And take the time to also install new cam seals (simple to do with the covers off the car), and either re-seal or replace the cam solenoids themselves (if leaking oil, which they often do from the plugs).

It's all detailed in my Top-End Refresh thread from last year, as well as on the @gsxr's site.

Yes, the cam covers should come off to do this job. It is also an EXCELLENT time to look at the timing chain rails and upper chain guides on both sides, to see if they need replacement. It is more work to replace the lower guide on the driver's side, because the tandem pump and/or pump mounting plate needs to come off the front of the cylinder head to get to the pins for the lower guide, but it is excellent preventative maintenance.

In addition, the cam adjuster mechanism needs to come off the end of the camshaft to get to the lower chain rail. It's easy to remove/disassemble this adjuster mechanism, but it is close to impossible to successfully re-install it with your bare hands. Some people have improvised tools, or even done it with their bare hands (perhaps a second person helping would work), but I gave up after hours of trying and many dozens of failed attempts, and purchased the MB special tool to re-install the adjuster mechanism. This tool allows the job to be done in mere seconds, and also works for M104 engines as well.


Replacing cam seals

Driver's side chain rail replacement

Cam cover re-seal w/orange koala-claw goo

 

[gsxr]

How this cover should be sealed to the head itself? Mine seems to be sealed with RTV or similar sealant and it is most likely passing oil. Not much, just enough to make the front of the head oily. Is it a big deal to remove it and re-seal? I can see that the camshaft cover will have to come off but this shouldn't be a big problem.

If that item was attached with RTV, it could be a bear to remove. This is why you should use the anaerobic sealant, which allows easy removal.

Note that oil leaks in this area are common, but don't expect re-sealing just that part to cure the leaks. The cam solenoid itself is probably responsible for >90% of oil leakage in this area, the oil runs down and along the bottom edge of the cover. If your cam solenoid is original, it WILL need either disassembly and re-sealing (JC200 posted a detailed How-To), or replacement with new (requires late style armature too).

If the cover was sealed with RTV, make sure the leak isn't from the cam solenoid... the cover itself may be sealing ok with the RTV. And as Gerry said, if you haven't done chain rails yet, definitely replace them all while this cover is removed.

 

[darek_u]

Gents thank you for your replies. My engine was rebuilt a couple years ago, it was stripped down to the bare block, all chains, rails, seals etc. etc. were replaced. I have 2 new cam solenoids as well as new cam seals. I'm 90% sure solenoids are not leaking as I installed them myself with Loctite 574. I narrowed down the source of oil to the cover however I cannot say solenoid is not seeping oil until I remove all covers etc. Anyway, it looks like the shop that did rebuild used RTV instead of 574 for the cover, shame on them.

 

[darek_u]

Gerry many thanks for the link to your thread with specific post about covers - one picture is worth more than 1000 words. Looking at these pictures one question arises - do I need to remove the cam covers as well? Judging from the pictures I would say no... Can you advise please?

 

[gerryvz]

Gerry many thanks for the link to your thread with specific post about covers - one picture is worth more than 1000 words. Looking at these pictures one question arises - do I need to remove the cam covers as well? Judging from the pictures I would say no... Can you advise please?

Yes, the factory instructions require that the cam (valve) covers be removed before the front cylinder head covers are removed.

I have attached PDF versions of the factory instructions. You will clearly see the prerequisite job of removing the cam covers (job 01-0500), in the instructions for the cylinder head front cover removal (job 01-2120).