An essential part of any oil change is the engine oil filter. Generally oil filters come in two styles, a cartridge style that looks like a bare filter, and a spin on variety. Spin on oil filters carry several features inside, such as the bypass valve and anti-drain back valve. On engines that use cartridge style filters, these components are often found inside the engine, commonly in the oil filter housing. It is important to use a quality oil filter as it is working to keep contaminates such as carbon out of your engine, and it should be swapped at every oil change.