Originally Posted by
gklug305@msn.com
I called Needs Wings and ordered a couple of items and ss I am on the process of installing new valve cover gaskets and changing the spark plugs I asked about how to seal the breather upper valve cover pieces..... that I had read black RTV gasket silicone was used. Maybe he was just trying to make a sale but he said Black RTV is NOT what to use. He sells a Mercedes sealant of some sort (about $37 I think) that Mercedes specifies.
I did not use the Black RTV sealant when I repaired the leaking crankcase covers on my 2007 Coupe. I used the
Permatex® Ultra Grey® RTV Silicone Gasket Maker, which is recommended for high temp (-65F - 500F / same temp range as Ultra Black) applications plus withstands high vibrations (engines do shake). I did my repair back in OCT, 2009 and no leaks thus far. But I also check the torque on all the fasteners every couple of years. I've found these to loosen up over time (probably related to the weak aluminum screws used by M-B in this application). I have marine grade SS screws (the small ones) so they can be re-torqued, if required. Since I check the torque on all the crankcase breather & valve cover screws, I've not seen an signs of oil leakage in these areas. The valve cover gaskets on my 2007 Coupe are the ones the factory installed.. I'm convinced that the Marine Grade Crankcase Breather screws, which allow me to perform a torque check every 2 years, are a major contributor to the non-leaking assembly thus far on my V6.