This vehicle has been completely rebuilt, when I take it out and hit 70 mpg it overheats, what could be the cause?
It only overhears at high speeds? Does it have an electric fan or a clutch fan?
Late model? Are we talking about a '86-'87 300SDL or a '90-'91 350SDL?
Has it been overheating since it was rebuilt, or is this something that developed later? Does it ever overheat at lower speeds?
How old is the car and why was it completely rebuilt? Who did the rebuild?