My 91 4 matic m103 engine, 183k is consuming/ leaking 1 quart every 500 miles. there is freh oil on right rear of engine, just under the head gasket area. I have read about front oil leaks and head gasket failures on these engines. There is a little oil on garage floor but most seems to be leaking and burning there is a smell and alot of smoke coming off of the engine after highway driving. I am pretty sure that the head gasket is the problem. does anyone have any advice on gasket replacement or anywhere that I can pick up a MB repair manual to help me with the project?