1993 Mercedes-Benz 300SE Q&A
1993 Mercedes-Benz 300SE Question: Oil going into the plastic coolant container.
If the coolant is disappearing with no visual leaks, then there are 2 possibilities. The coolant is leaking from the heater core inside the dash, you would smell coolant inside the car and have wet carpets though. The other is coolant is getting into the combustion chambers via a cracked head/block or leaking head gasket. Since you have oil in the coolant and your losing coolant, I think it's the headgasket block/head crack. To check for these, please look at this article: http://repairpal.com/testing-for-head-gasket-failure - Bret Bodas
The head gasket should not apply to this problem. More than likely its the valley pan gasket. It seperates the water coolant from the oil. - Visitor