Last year, my son gave me a black 1985 Mercedes Benz 300D Turbo with leather seats, sunroof etc. as a gift. He was the second owner, the original owner was a little old lady living in Pittsburgh who babied the car and drove it to the store and back (classic story). When she died it had 70,000 miles on it and her grandson sold it to my son, . He drove it cross country to Los Angeles, but because he travels internationally 10 months out of the year he decided to give it to his mother as a gift. At the time it had 75,000 miles. There were some electrical problems which were fixed but then it developed a terrible noise and we stopped driving it. I checked the oil and it looked like it ran out (the indicator had not given me any warning). I have it at a repair shop (supposedly reputable) and the mechanic checked the rocker arm (to see if it was something simple) and now he says he needs to pull the engine, and said given the mileage it might be worth repairing by putting $2600-2850 to repair, if it is more major he recommended a rebuilt engine costing $3500-4,000. I am torn as to what to do, invest money to repair the engine (and the oil indicator light!) or sell it to someone who can nurse it back to health (and if so what would it be worth). Advice is welcome!