I have a great driving 1985 300SD. It has only one serious flaw: it gets about 250 miles per quart of oil. It smokes very little - just a little black smoke on hard acceleration. My mechanic and I have replaced or checked everything we can think of, i.e., new timing chain and valve seals, fixed 2 small leaks and car now does not visibly leak at all, checked turbo for leak, etc., etc. The car runs smoothly and has good power for a diesel. The compression has been checked and the readings are all between 380 and 400 except for number 2 which is 350 (still not very low). I don't understand how an engine can have decent compression, very little smoke, and yet burn this much oil. Has anyone seen this before ?