I Heard Synthetic Oil Caused Engine Failure In Airplanes..?
These stories and rumors are based around Mobil AV-1, Mobil’s attempt at marketing a synthetic aviation oil in the early ’90s. This has no relation to the Mobil 1 synthetic oil for automobiles. It was mostly the larger, high displacement (and higher blow-by) engines were having problems with AV-1. Mobil eventually owned up to the top-end damage (sludge buildup, piston ring malfunction and piston blow-by resulting in cylinder/piston damage and high oil consumption.) But they denied the bottom-end damage many people claimed were caused by AV-1 (camshaft lobes, crankshaft/connecting rod bearings and counterweight dampers) even though the FAA said they were sufficiently documented (FAR 21.3). These problems typically took 250-500 hours to occur. AV-1 went off the market after a few years. The FAA rescinded Mobil’s STC for AV-1 in May 1996, which was announced in the FAA General Aviation Airworthiness Alerts (AC 43-16). There was a settlement for a class action lawsuit for people who’d used
