Recently we purchased our first w210 - a 2002 E320 4Matic sedan. Car seems to be just about perfect in and out. Engine and transmission are very smooth. However, in looking under the oil fill cap, there is quite a bit of yellowish creamy "gunk" stuck to the cap, and a bit around the filler neck. Is this normal for this engine, due to condensation, or PCV system, or similar? Cleaned it out and some has already returned. Oil on the stick is perfectly clean, despite being nearly ready for another oil change. Coolant is also clean and at correct level. By the way, the car only has 28,000 miles on it, one older owner.

Aside from this oil gunk, what other issues are there to watch out for? No rust yet.

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2002 Mercedes-Benz E320 4Matic
1995 Mercedes-Benz E320 Wagon
2005 Land Rover LR3 V8 SE
1999 Audi A8 4.2L quattro