Cam Breather Tanks Leaking - SL55

[SL63 Mark]

Had my A service yesterday at MB Salisbury, including brake fluid change. Service advisory states "cam breather tanks are leaking", so I asked a couple of questions. Apparently they're under the air filters on top of the engine and are prone to leaking oil. MB offered to clean and re-fit, but I said no, as I fancy having a go myself, as it sounds a nice DIY.

Has anyone any experience/advice of doing this ? Any pictures/diagrams of what they are, where they are, how to get them off, before I launch in with the spanners ? Also, what exactly is their function, as it's always important to understand this.

Many thanks

Mark

 

[WG M-B]

They are pretty straight forward to re seal Mark. Remove the air cleaners, then the breather housings ( you will see them bolted to the top of the valve covers )
The breather pipes will be brittle and probably split on removal ( available from mb for pounds and pence )
Once removed you will notice there is no gasket as such, just a silicone seal !
Clean thoroughly and use brake cleaner to be double sure!
You will then need to very carefully reseal using the mb silicone sealant ( I recommend this product ) and refit / re torque !
You must torque the bolts to the correct setting as they can snap very easily!!!

 

[Uncle Benz]

I'd recommend you remove the cam covers before removing the breather boxes. Particularly the offside, as the oil drain back to the sump on the rear of the engine contains a very small drilling. If you drop a small piece of the old silicone down there it could block the drain back and have big consequences.
The small screws are aluminium and shear very easily. If you order new ones from mb they will be steel replacements, and more robust.

 

[SL63 Mark]

Thanks Terry and Uncle Benz, I'll order the pipes, screws and sealant from MB before I start, and post some pics up here of the job. Any idea what torque the bolts should be, Terry ?

 

[SL63 Mark]

Well, I finished the job today, both cam breather tanks removed, cleaned and re-fitted, using MB silicone sealant. Here is the off side tank removed, showing old sealant still in place. I found it easier to remove two of the coil packs for easier access. The big V8 looks impressive with all it's covers removed :

Here is the engine with the near side breather tank removed - this tank is twice the size and took some time to clean with brake cleaner, making sure no tiny bits of silicone went into the engine, where they could cause damage. All four coil packs had to come off the make access easier for this side. The pipes were not leaking, so I did not replace them at this stage :

Here is the off-side tank cover on the bench, with some of the tools required for the job. Sockets are T25 and T30 torx bits, plus E10 female torx socket. The aluminium M5 torx headed fasteners were replaced with steel screws :

 

[WG M-B]

Well done Mark
Good job