So this engine has a replaceable cartridge under a large aluminum retaining cover, and the O-ring goes on into a groove on the cover? Please make sure that anyone changing the oil uses the proper SST for opening it, and it is put back in exactly as specified. It has two flats that go in specific places and it is tightened to specifications. If they ever use a hammer and large screwdriver to bang it open or close, it will crack after a few times.