I have a '95 C280 with the M104 engine. I was checking the coolant level and noticed a few small (1-2mm diameter)oil slicks floating around in the coolant. Is this the begining of the infamous M104 head gasket problem? I don't know where else oil could enter the cooling system. There is no coolant in the oil and the car runs fine. (no over-heating or other problems). The head gasket was replaced under warranty at 33,000 miles by the previous owner. The vehicle now has 92,000. (no extened warranty). Any technical advice would be appreciated.