White residue
 

I have a 2000 E430. I’m getting a white sludge material forming on my oil fill cap. Much like a head gasket leak when coolant mixes with the oil. My local Mercedes mechanic said that certain brands of synthetic oil cause this and it’s also a sign of the oil not being changed often. Is this correct? He recommended replacing a quart of motor oil with transmission fluid to clean the engine for about a 1000 miles!!! Is this safe? Should I do this?

Thanks, Matt

RE: White residue
 

If this were a brand of car that used a PCV valve, I'd tell you it's clogged.

The white stuff is a result of poor crankcase ventilation. I don't know how M-B does crankcase ventilation but I'm pretty sure they do it somehow. I only know they don't use PCV valves.

There's probably moisture in your oil (which adds to the white stuff), so I'd change it out. If you add trans fluid to the oil it won't hurt it and it will clean some, but it's more important to remove any moisture that may be mixed in. Just change the oil after you determine that the crankcase is being vented properly.

RE: White residue
 

Plus change the oil a few times after more often than normal oil is cheap a rebuild isn't.