[psfred]

There are three reasons why a new gasket might leak.

The first is that the cover is warped, usually from serious overtightening. You can check with a straightedge. And yes, a little judicious filing is sometimes necessary on the "stops" on old covers. Be careful, as the cover will cut the gasket if you file too much off.

The second is overtightening the screws and cutting the gasket -- this is usually a problem on the older (615) engines -- the 617 and 616 have the "stops".

The third, and most common problem, is improper installation. The drill follows:

Remove cover. Remove old gasket a completely clean the cover. All oil and dirt, etc must be removed from the edge that goes into the gasket.

Wipe down head with solvent -- paint thinner, carb cleaner, etc. The head must be completely clean and DRY -- no oil anywhere. If there is oil under the gasket when installed, it will leak.

Place gasket on head and insert valve cover, then slightly lift cover and bang down firmly on head. Make sure you don't have the gasket out of place on the first thump, or you will likely cut it.

Lift cover again and bang down, repeating until you get a good solid sound -- it will be obvious -- a nice loud "clop" instead of a "thub".

Install screws and tighten just slightly past were the steep resistance to turning starts. You may need to shug up a bit more, but not much.

This is the official MB method, as taught in Germany. If you don't bang the cover down hard to seat the gasket on the cover, it leaks out over the top of the gasket.

I'd take your's off and re-install using this method -- should cure the leak.

Don't use anything to hold the gasket to the cover, either -- it will leak!

Peter