I have a 93 Ford f-150 with a 302ci with 138000 miles. I have own the pickup for the last 4 years and 60000 miles. I have ran convention oil (mainly Case IH 15w40 with 30 micron fleetguard filters) I have recently become interested in extending my OCI mainly becuase I am about to graduate from Texas Tech and have a new job with the NRCS stating this June. I will commuting about 500-600 miles per week and really don't want to change my oil every month. But I know my pickup has some wear on the rings and cylinders and a small leak around the oil pan gasket (couple drops a night). With all that said I have recently purchase Schaeffer 5w30. Under what situations is Schaeffer the best, and what situations is it not? Should I be running 5w30 in something that is unfortunately going to have a little blow-by? What length of OCI do I need to use? Should I start out with shorter OCI to rinse the engine? I know as soon as I put new oil in my pickup and pull the dipstick the new oil is already blackish. I asked about shorter OCI the first drain. I want to eventually run a fleetguard 10 micron, but I don't want to be rinsing with a 10 mic filter? Should I start with a 30 mic the first drain while rinsing then increase to a 10 mic? What are your thoughts on running 10 mic filters for long OCI? What is a good OCI for 10 mic filters. What are your thoughts on Fleetguard Filters? I work at a Case IH dealer untill I graduate and all of the Case IH filters are Fleetguard and I have heard that many other brands are made by fleetguard? What is the typical efficiency of a bypass filter? Do they only filter when the bypass is used? B/c when looking at the routing of the lines of bypass filters it looks as though it is just a secondary filter rather than a bypass? Is that correct? Can one make there own "bypass filter" if they have a filter base that has in and out lines? I know this is a heck of alot of questions but I am really interested in which oil is the best and what filter combination works the best . Something that I might want to add is that I live in West Texas, where the dirt BLOWS! Thank you for your time!