Was curious about how epoxy holds up with oil and vibration of an engine. I had another thread where I was wondering how to secure the oil pump pick up strainer to the pump, but I would like to know because I had a hole in the front cover where one of the water pump bolts were. If you look on the inside of the cover there are little bumps where the bolts screw in on the other side. Well one of these was broken through so I filled it with some 5 min 2 part epoxy. If it ever breaks out of there could a hard piece of epoxy be a serious threat to the engine floating around in there.
On engines it's a lot better to use JB-Weld. You can get it at any parts store and lot of other places. If the piece comes off it probably would just lay around in the oil pan and not hurt much.