Oil filter housings securely mount the engine’s oil filter and maintain oil flow to the lubrication system. Commonly constructed from aluminum or reinforced polymer, they feature threaded or gasketed connections to both the engine block and filter. Internal baffling may direct oil flow for optimized filtration and cooling. Housings incorporate ports for oil inlet from the engine and outlet to the lubrication circuit, with pressure relief valves present in some designs. Variations exist to accommodate spin-on or cartridge-style filters, and are located directly on the engine block or remote-mounted with connecting lines.