Internal and External engine oil & coolant leaks can develop from the head gasket and/or timing cover gasket; these leaks should be repaired before the engine oil and coolant intermix which can result in severe engine damage.Google+
Car Problem Reports
Mercedes-Benz 300TE Repair Leaks From Head Gasket/Timing Cover Gasket Before Oil and Coolant Intermix
Mercedes-Benz 300TE Problem
Visitor, 1991 Mercedes-Benz 300TE, 170,000 mi
Engine oil turned milky, which of course means engine cooling water is mixing with oil. Obviously the head gasket is gone pushing oil into the cooling system. I went to NAPA, for $40.00 bucks on the advice of a guy behind the counter said give a head gasket sealer a try. So, what the hell. I forked over two twenties, dumped the stuff in (not even cleaning out the milky scum in the expansion tank) and - hey, its been working for over a year now.