Hello Aaron;

Here is my prediction, based on tearing apart our 190e 2.6 twice (at 270,000 and 350,000 kilometers). Pure speculation, of course.

The cam chain will show no wear at all. Depending on age, the plastic cam chain guides may be brittle, or the tensioner may have lost its grip, but you would be hearing the awful clatter.

The valve guiides will show no wear at all. They should not wear much, since the valve train geometry places very little side thrust on the valves. Mine were still perfect at 350,000 km (220,000 miles). Everybody talks about replacing them, but I don't know why. Fear of not doing enough, perhaps.

At that mileage, the rest of the valve train is probably just fine. If it is clattering, there may be a sticky lifter. (Yes, it does have little hydraulic lifters built into the rocker arms.) The camshaft is probably not worn at all. You can see all this just by upening the valve cover.

The head gasket is still sealing well. However, the little front rubber gasket, under the distributor cap, is probably hemorageing oil. It could be causing your puddle. No need to change the head gasket: just try to seal up the front cover. I say "try" because it is notoriously leaky no matter what you do.

The valves could probably stand being lapped into their seats, if you feel like doing a tedious task and have the head off anyway. No need to take it to a professional to grind the seats and valves. (Except for the fear factor, of course.)

The valve stem seals are completely ineffective. The 15-year-old rubber is so hard that they might as well not be there. They are passing an amazing amount of oil, which is burning in the combustion chamber, fouling the plugs, upsetting the emissions (high unburned hydrocarbons), and is at risk of fouling the catalytic converter. You can get the seals replaced without pulling the head, but It is hard to do without special equipment.

So: I think that you probably have two problems: the leaky front cover causing the puddle, and leaky valve stem seals. For what its worth!

Andrew