What's inside an oil filter and how does it work. A good oil filter will have an anti-drain back valve to help keep oil from draining back tonthe oil pan when the engine is shut off. It helps keep the filter and oil galeries full or oil and primed. The 2nd valve a good filter should have is a bypass valve. When the engine oil is cold it's too thick to flow thru the filter element, so rather than starve the engine of oil the pressure build up will unseat the bypass valve allowing oil to flow arou

Cutting an old oil filter open is a great way to learn more about what's going on inside your engine. The best and easiest way to do it is to hrab yourself a filter cutter. It's basically a bigger version of a tubing cutter. It centers in the threads of the filter and you tension the cutter wheel slightly and spin. Light tension is best and lots of spins, let the cutter do its work. Be careful once its cut, it leaves a sharp edgs. All oil filters are NOT created equally. A good filter will have