My father owns a 1990 SL300 with 185,000 miles. It still runs great but has developed an unusual oil leak. A very small amount of oil (a couple of drops) shows up in the anti-freeze but there are no signs of any water in the crankcase. I was guessing a cracked head or a blown head gasket, but not sure. With that kind of mileage he is trying to decide if its time to let it go or invest in some repairs. Any thoughts out there as to the possible cause?