Quote: What Amsoil says is that the oil is good for 25000 miles. You change to their oil and filter, and when you reach 12500 miles you replace the filter and add a quart of oil, then drive another 12500 and your ready for a complete oil change. If you are using the by-pass filter along with a full-flow filter and have a oil sample checked in the lab you still change the filters and add oil put you dont change the oil untill the sample does not pass.
The oil filters you are referring to is outdated filtration technology.
