Oil sight glass with G 1 1/4" male thread G 1 1/4" · outer diameter 47 mm · spanner size 40.5 mm

Product detailed description

Oil sight glass

A replacement oil sight glass for a compressor with a G 1 1/4" pipe thread. Outer diameter 47 mm, window 30 mm, tightened with a 40.5 mm spanner. Transparent PA-T technopolymer body, NBR seal, working temperature up to 100 °C.

An oil sight glass is a window into the oil sump for checking the oil level. The window is shaped as a magnifying lens, so the level stays readable from the side, and inside sits a contrast star of matt anodised aluminium with a red centre — the level reads better against it than against a bare window.

Sight glass dimensions

Fitting and tightening

Drain the oil or tilt the machine so the level sits below the opening. Unscrew the old sight glass, wipe the seating face dry and screw the new one in with the seal that comes with it. Do not reuse the old seal — hardened rubber is the most common reason oil weeps around a sight glass.

It is tightened by the hexagon, with a 40.5 mm spanner, to 8–10 Nm. Keep to the torque — the plastic body is easy to overtighten and crack, and too little will leak.

What destroys it

It must not come into contact with alcohol or with cleaning agents containing alcohol — the technopolymer crazes afterwards. When wiping oil from around the sight glass, use an alcohol-free degreaser, not a spirit-based glass cleaner.

Replace it as soon as the window has yellowed, clouded over or cracked — without a readable level nobody checks the oil. It pairs well with an oil change, since the oil has to come out of the sump anyway.

Ventilek says

It is a part worth pennies that the whole machine hangs on — without a readable window nobody checks the level and one day the pump seizes. Replace it at the next service and tighten it to a torque, not by force.

Dimensions, material and tightening torque follow the manufacturer datasheet attached to the product. All dimensions are in millimetres.