Collection:Oil Level Sight Glasses

Oil level sight glasses show the oil level at one point of a reservoir, gearbox or hydraulic tank through a glass window. They screw into a threaded port in the tank wall, so the level can be checked at a glance without opening the tank or pulling a dipstick.

A sight glass is fitted at the height of the level that matters, usually the minimum or the normal filling level. Some sight glasses have a reflector behind the window, which makes the oil level easier to see. A metal body with a glass window tolerates high temperatures, which makes sight glasses suitable for gearboxes and hot oil systems as well as for hydraulic tanks.

Select the thread size of the tank port, and check the pressure and temperature rating against the application. Use a suitable sealing ring so the thread does not leak. A sight glass shows whether the oil is at one point; to read the level over a range of heights, choose an oil level column indicator instead.