[Marshall V. Daut]

I add a flat washer between the pan bolt head and lock washer to spread out the tightness. Sometimes the slots in the repo engine pans are too wide so that the lock washer slips inside the slot, allowing the pan to become loose and make screeching noises as the tips rub against the oil pan. The flat washers will be wide enough to cover the flanges and keep them tight against the oil pan rail.
Marshall