Brands of Oil
On the subject of oil (again). Is there a brand that is better suited for keeping the engine internals clean. I just purchased a '92 300e and looking inside the valve cover there is a black buildup on the cam and rockers. The car has 105,000 miles and was very well maintained. My old '88 260e with 142,000 miles and it is so clean inside you could eat off it. I'm trying to figure out why the one engine is so dirty. I came up with two possibilities:
1. The 300e might need valve stem seals. Combustion gases are getting into the valve cover.
2. The previous owner used a brand of oil that didn't have sufficient detergents to keep the engine clean.
Anyone else have any experience with this concern?