OK I put my feelers in the tool box. They can't be hurt. A filter is better than no filter. Can we agree on that? Full flow filters have a bypass valve. Can we agree on that? Why? So the filter is not damaged and rendered useless by over-pressure. When the bypass valve is open..there is no filter in the system. In a perfect engine, there still will be stuff that breaks down the oil. Water, acids, and other chemical processes. Oil wears out. Can we agree on that? I have never seen a perfect engine...never. We have old engines, but access to modern filters. Yay! We have access to modern oils..Yay! I like the bypass filter system. It works. I like the full flow system. It works. My engine won't see a machine shop just to put a full flow filter on it. My choice. I won't take out the full flow filter on the wife's' much more modern car, why?, cause it was designed to have one. Running both a full flow filter and a bypass filter? Makes sense for some operations more than others. Some engines are very efficient and produce less chemical reactions. Some fuels are less likely to make those chemical reactions. Some engines are operated in an environment that bears very little resemblance to my truck. I start when cold, Take short trips, I start when damp, and might not get to operating temp before the trip is over. I some times do this many times a day. And my truck is ..old. I change the oil and the filter...maybe I could get away with keeping the filter..but it is 10 bucks. Less than 1/2 the cost of the oil...I am OK with that.
