I was looking at a 635 and saw that what looked like oil smoke was coming from all around the head. I looked at the coolant but it looked fine no oil mixed in. any ideas? This car has plus 300k and its a 88
thanks
steve

Did you check the oil for coolant? It usually works that way if the head gasket is blown. Smoke coming out from the head can't be a good thing.

is the valve cover gasket leaking?, does it overheat?, check the bottom to see if oil is leaking on the ground

i would look very closely for oil leaking before even thinking of the head gasket. the oil pressure switch near the rear of the head has a nasty habit of springing a leak, and when bad enough leaves a small puddle.