I brought a 1979 300CD to a local MB mech. I'm thinking of buying the car. He tells me theres a considerable amount of blow by and he's concerned the motor may not last another 50k.(Then again, he says, it might last another 100K...He just can't say) I pulled the oil filler cap and there is quite a bit of smoke coming out. Question is: how much smoke is normal to be coming out of the valve cover for an engine that might have 300K on it. (speedometer's broke @ 170K). Is rebuilding the entire engine necessary or can a valve job work(or is that basically the same thing). Basically I'm looking for options.

The engine starts right up. No noticable smoke at start-up. Good power and reasonable accelleration for this car.

It has the usual wetness at the valve covers and is pretty wet underneath. However I just found a line from the valve cover that goes to the air filter that was disconnected and was leaking all over. Who knows how long this has been like this..?

Thanks for any help
Steve