I feel for the poor guy at the overhaul shop. I've had to investigate several 535 oil smell enignes, when they are torn down you can see nothing obviously wrong with them. You just have the re-line all the oil/air seals, replace the oil pump for a new unit and off you go again. One particular engine failed 3 times before we fixed it.
TWApilot - interesting point about those screws - anybody know of any a/c type doing this?
Regards,
N1 Vibes