Oh, I forgot to mention that the engine recently developed a coolant leak at the right rear head gasket. It is a fairly severe leak, so the head has to be removed. The valve job was just something I knew I should do if the head gasket ever had to be replaced.

And by the way, two of my Mercedes club buddies have 617 turbo diesels with head gasket leaks and simply cleaning up the head and replacing the head gasket failed to cure the leak. So there is a fair amount of wrenching involved to cure head gasket leaks on these cars.