I have a "rust bucket winter beater" 240D here in MT that starts great above 15 degrees F and really hard below (if at all). I ran diesel purge through the other night and did a compression check. All cylinders were 325-350 save #1 at 180. The valves were adjusted in September...but #1 on this 240D was the first valve I ever adjusted on this car (and it was hard to do, and hard to get the locking nuts tight.) Could I have screwed it up? The leakdown reading on #1 was 450...so methinks not valves...rings. How much compression can a bad valve adjustment lose?