Abstract: This invention relates to a reusable filter unit for an internal combustion engine wherein the filter fulfills both a filtering function and an additive function, the filter including a filtering part with replaceable filtering media and an additive part adapted to receive replaceable chemical additives. The filter part includes a generally toroidal shaped plastic element for receiving a generally cone shaped replaceable filter media, which can be agglomerated fiber, the element fitting into, and permanently bonded to, an outer shell, with the additive part being located below the element.

Abstract: A self-venting valve apparatus using a valve stem rotatably and slidably mounted to a vessel by a collar is disclosed. The stem includes threads at the top and base of the stem which matingly engage internal threads of the collar to hold the stem open or closed. A single gasket seals the gas inlet and liquid outlet in the closed configuration. To drain the fluid, the valve stem is unscrewed so the bottom threads disengage from the collar, the valve stem lowers until the top threads of the valve stem engage the collar, and the top threads are screwed to the collar to secure the valve in the open position. Fluid begins draining through the central passage of the valve stem before gas enters the vessel through the groove in the sidewall of the valve steam to allow proper siphoning. The lower end of the liquid drain passage is placed below the lower end of the air inlet groove, thereby insuring that the liquid drain passage is opened first as the valve stem is lowered.