I have a 1990 525i, The low coolant light comes on (has been doing this forever, I think it is the sensor), but recently the low engine oil light comes on after you turn the car off. I checked the engine oil and it is at least 1/2 way up the dipstick. I looked in the radiator as the coolent looked an inch or so short, and saw some murky stuff in there. After stuffing a paper towel down there, I pulled up what can only be described as green thick soup. I guess oil is getting in there from someplace, but there is no antifreeze in the oil at all. Where could this be coming in from. I had a new head put on there last summer and the car doesn't even have 5000 miles on it. Any ideas or suggestions. Also, there is no white smoke on start up or when the engine is running. The engine does not overheat.
Thanks, Joe