Abstract: An oil reconditioner for use with an internal combustion engine is provided for returning the reconditioned oil to the engine under pressure. The oil reconditioner has an oil filter chamber into which a first portion of a pressurized stream of oil from the high pressure side of the engine is directed so that the oil may flow through the filter chamber and into a heated vaporization chamber thereabove for vaporizing any liquid contaminants within the filtered oil to thereby recondition the oil. The reconditioned oil from the vaporization chamber is directed into and joined with the pressurized unreconditioned portion of the stream of oil that has bypassed the oil filter and vaporization chambers so that the reconditioned oil will return to the engine under pressure along with the pressurized unreconditioned portion of the stream of oil.