Date registered: May 2005
Vehicle: '07 GL320CDI
Mentioned: 0 Post(s)
Quoted: 1 Post(s)
This is more likely antifreeze than oil. The coolant can wash over an oily spot and then look like oil. To check whether this is the case, just understand the difference in smell between antifreeze and oil.
Antifreeze escaping coincides with overheating, which is possible in the high-stress situation you've described. Of course antifreeze on the exhaust makes steam while oil without question makes smoke. Smoke is a prelude to fire, so it's more serious. Oil smoke is likely to have a blue tint, antifreeze steam will be just white. Smoke hangs around and settles, steam dissipates.
By design, antifreeze can indeed escape when cooling system pressures get too high. Also by design, motor oil is never supposed to escape, so that means without question an equipment malfunction if it does, and that should be investigated by professional mechanic with Mercedes experience.