i called my mechanic and clarified a point. the engine was not stopped at top dead center. he was able to turn it to TDC by turning the crank, then turning the cam to unbind the chain, then turn the crank, then the cam, etc. so something is causing the chain to bind down low where we can't see. again, no debris was found in the oil pan.

i have a snake light with a camera attached. i think we'll try to look up from the bottom with the snake light camera and see what we see

but if you were me.... how would you proceed?

i'm thinking dive into the front first, taking off the chain cover and see what we find... replace chain and all guides since we're there already. assuming we find a problem .. say a broken guide down in the lower part of the chain area (not very good at the technical language) would you just go ahead and do the heads and valves as well? my mechanic (who is mainly a diesel guy - i have and 84 and 85 300SD) is thinking we just go for it and hopefully end up with a basically renewed engine that will go for the next decade.

i don't want to spend the thousands of dollars if not necessary but don't want to be penny wise and pound foolish.

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R Martin
Dallas, TX (Addison)

86 560SEL, 128K