Abstract: A system for maintaining a desired level of fluid in a sump, such as maintaining a desired level of oil in the crankcase of an internal combustion engine, is provided with an oil reservoir having a cap which assures sealing of the fluid inlet of the reservoir, an outlet valve with a tiltable operator rod which provides assurance oil will not flow from the reservoir when the inlet cap is removed and which facilitates the addition of oil to the reservoir through the inlet and a sight gauge having guard members which assure the structural integrity of the sight gauge.

Abstract: A liquid level sensing probe for gravity induced flow liquid level regulators used for maintaining a desired level of a liquid in a sump of a device having moving components within or adjacent the sump, such as maintaining a desired oil level in the crankcase of an engine, increases the accuracy of the regulator by being resistant to wind forces which impinge upon the liquid and gases entrained within the liquid.

Abstract: A system for maintaining a desired level of fluid in a sump, such as maintaining a desired level of oil in the crankcase of an internal combustion engine, is provided with an oil reservoir having a cap which assures sealing of the fluid inlet of the reservoir, an outlet valve with a tiltable operator rod which provides assurance oil will not flow from the reservoir when the inlet cap is removed and which facilitates the addition of oil to the reservoir through the inlet and a sight gauge having guard members which assure the structural integrity of the sight gauge.

Abstract: A standpipe type sensing apparatus for a barometric or gravity induced flow oil level regulator for maintaining oil in an engine crankcase at a desired level has a vent which places an air space in the standpipe in fluid flow communication with a relatively oil free portion of a relatively calm air space above the oil level in the crankcase. The vent assures that the air pressure in the standpipe air space and in the crankcase air space are substantially equal during operation of the engine. A fluid flow damping orifice is provided to retard the rate of fill and drainage of oil from a sensing chamber in the standpipe. The standpipe apparatus is readily installed onto engines without the need to remove the oil pan.