This month’s Ask a Tech Q&A comes from the owner of a Lycoming O-235 engine who’s chasing oil leakage, plus the owner of an older Beech Bonanza is trying to figure out why some of the avionics in his panel shut down on hot days. First, IA Mike Berry has some thoughts on the leaking oil.
“After a thorough cleaning and subsequent ground-running of my Lycoming O-235, I found that the through-bolts and cylinder deck studs (short) are leaking. Troubleshooting requires running the engine at 1800 rpm or higher to initiate the leaks. After two or three minutes of running at 2000 rpm, oil can be seen at six of the studs. The number-two cylinder has a leak at the through-bolt in the two-o’clock position that runs down to the bottom of the case.”