Abstract: A quick-change oil filter/reservoir system for an internal combustion engine is provided in the form of a cartridge or canister containing an oil filter and precharged with a fresh supply of engine oil. The cartridge is releasably carried on a mount by quick-release fasteners and includes non-manipulative, self-sealing input and output fittings on the bottom surface which engage corresponding oil lines provided on the cartridge mount and connected to the engine oil pumps. In addition to the engine's primary oil pump, a secondary or scavanging oil pump is provided to continuously return engine oil from the engine's sump to the filter/reservoir cartridge. To accomplish an oil and filter change, the used cartridge, containing the used filter and the bulk of the used engine oil, is merely replaced with a new cartridge containing a fresh filter and engine oil.