C63sydney

As title suggests I went to a track day the other day and had a fair amount of oil weep from the filler cap and onto and around the rocker cover.

Before I went to the track I triple checked the oil level on a hot engine and it was just perfect.

This is now my second C63 and have not had this happen as severely before.

Any informative responses appreciated.

CPD SLK

Wow...if the level is correct, it's tell me that either somehow the cap wasn't sealed properly or maybe your engine got so hot the oil spewed out the top? I'm not expert, but I'm sure the engine would have to get ***** hot for that to happen, and if that did happen, you'd know and have other issues...so I doubt that's it...

Maybe the cap just wasn't on right??? Guess we'll let the experts chime in haha

Diabolis

The cap wasn't seated properly. Oil is not coolant and it does not turn into steam to blow the cap off.

jrcart

You need a Weistec catch can/separator breather, it's a simple fix and highly recommended if you track your car. Crank case pressure can be high on these motors. I blew my dipstick out at a track event at Willow Springs in my CLK BS when my motor was still NA.

Diabolis

You shouldn't build up THAT much crankcase pressure on a NA car. The rubber O-ring on the dipstick does deteriorate from the oil over time and it can become loose, or you could have a clogged PCV / breather hose (whatever MB calls it). It can also be too much blow-by due to worn piston rings, but that would be unlikely if you're not seeing a high oil consumption and/or blue smoke out of the tailpipes.

While an oil separator / catch can is going to pull the oil out of the EGR gasses and prevent it from entering the intake manifold, it won't do anything to relieve excessive crankcase pressure since it uses the existing vent holes and just connects in front of the existing PCV. It's a great add-on especially if you're going to track the car, but again, all other things being equal it won't solve the problem.

Critter

Sounds like a PCV issue, too much crankcase pressure, excessive blow by, too much oil in the crankcase, high RPM.

Merc63

The crank case breather valve has a rubber flap that can tear off rendering it useless.

I'd say either the cap wasn't installed right or you're getting excessive crank pressure.

You can remove the Crank breather and pop the cover go check the flap. Might need go remove your intake tho.

KBC63

I experienced the same thing on my 2010. Problem fixed with a new cap.