I have a 99 Subaru that has develop oil leaks arround the pump and cam shaft seals. It is still under warranty but Subaru refuses to honor it because they question proof of maintence. Would oil changes on a regular basis have prevented problems with the oil pump leaks, lifter knocks, and cam seal leaks. ? Is anyone else having similar problems?. Thanks, Dave. e-mail.. ddesp95802@aol.com