Oil Warning light on Merc

I have a 2010 AS Devon and had an oil change a few months back, now after running about 50 miles Oil light warning light shows too much oil, I have had the oil level checked but the light still comes on usually at about 60 mph or above. Also Coolant level going from MAX to MIN after about 100 miles, can anyone help or suggest what could be wrong. Only done 13000 miles.
Pete C

If coolant is escaping into the engine oil you risk engine damage, so I would take it to a Mercedes service centre immediately and explain the problem.

Others with a detailed knowledge of that make of van may be able to suggest common causes, but in general (not Merc specific) possible causes could be failure in the water pump, failure of an oil cooler or failure of the head gasket in the engine. An approved service centre should be able to identify if it is the latter by testing the coolant and oil.

I would not drive it any significant distance in its current state.

Thank you for your quick replies, I will post the outcome when and if solved.

Good luck, hope it's something easy and not too expensive. 

Progress so far, Expansion tank on cooling system as a slight split causing water loss, Oil sensor being replaced, hopefully should be back on road by next Tueday.

Fingers crossed a good result 

Could be around £650 or 850 including a full service

Oil Sensor is in Sump, hopefully problem might be over

Water leak from slight split in header tank only leaks when coolant is hot and split expands, New Header tank fitted, Problem fixed. Oil switch in sump replaced only a good run will show if this has worked.