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