A method of filtering engine oil circulating in an operating internal combustion engine comprising the steps of:
- A. providing an oil filter assembly including:
- a canister open at an upper end thereof and including an oil inlet orifice and an oil return port connected through a lower end of said canister, said oil return port being located centrally in a bottom of said canister;
- a fiber filter element disposed in a lower portion of said canister and against said bottom, said filter element structured to remove solid contaminants from oil entering said inlet orifice and passing upwardly therethrough;
- a perforated plate positioned atop said filter element and including perforations formed therethrough which allow passage of filtered oil passing upwardly through said filter element;
- a filtered oil cavity formed between an upper surface of said perforated plate and a lower surface of a separator plate, said separator plate including separator orifices formed through an upper surface thereof through which the filtered oil under pressure within said filtered oil cavity flows;
- a lid sealingly connected to the open end of said canister, said lid having a central portion which slopes downwardly toward a central axis of said canister and is spaced above a similar sloping central portion of said separator to define a heating channel extending downwardly and inwardly to an oil drain insert connected to an upper end of an oil drain passage, said oil drain passage passing centrally through said filter element extending to said oil discharge port;
- a heating element in fluid isolation from, but in close proximity to, said heating channel above the central portion of said lid to heat and vaporize liquid contaminants in the oil passing and decompressing into said heating channel from said separator orifices, the vaporized contaminants discharging upwardly from said heating channel through a vapor vent formed in said lid, the oil passing by gravity through said drain insert and said oil return port;
- B. operating the engine after said filter assembly is attached to the engine to flow engine oil into said canister by internal engine pressure through said inlet orifice and then upwardly through said filter element and the perforations to remove solid contaminants from the engine oil;
- C. decompressing and heating the oil within an upper portion of said filter assembly to vaporize liquid contaminants in the oil within the heating channel;
- D. allowing the vaporized decontaminants to vent from the vapor vent;
- E. draining the decontaminated oil by gravity downwardly in the heating channel into and through the central drain insert and back into the engine through the oil return port.