Oil Pressure Gauge

Maintaining proper oil pressure is crucial in the longevity of a car engine. With a forced lubrication system that was invented by Frederick Lanchester, the oil pump picks up the oil and forces it through the drillings or oil galleries into the bearings that are the most highly stressed, like the main bearings, or the big ends and camshaft bearings. Oil jets lubricate the cam lobes, cylinder walls, and other components. Oil  pressure gauge

Having the right amount of pressure will make sure that the metal of the journal or rotating shaft and the metal of the bearing shell will never touch. This helps reduce wear to only the initial engine start up and shut down. The rotation of the shaft, combined with the oil pressure will center the journal in its shell hydronamically.

As you see an increase in bearing clearance from wearing and the declining in oil pump efficiency with age, the pressure will also decrease. After some time, it may be too low to protect the bearings, particularly if the engine is lugged at low revolutions per minute. Some engines have a gauge to show the pressure at any particular time, but others just use a warning light to show if the pressure is too low. Either way, the sensor will usually be mounted close to the engine's oil filter, by the oil pump.

Oil pressure is often higher if the engine is cold. This is because of the viscosity of the oil and also increases in engine speed. Pressure will be at its lowest when the car is hot and idling, and the minimum oil pressure allowed by the manufacturer is usually the case at this point.

If pressure is too high, you could have a filter or oil galley that is blocked or you might have the wrong grade of oil. Some older gauges are labeled using the term "druck" or "drucks". But newer model cars either don't have oil pressure gauges, or will instead have status lights, or a oil pressure gauge labelled with a pictograph.