| Maintaining proper oil pressure is crucial in the | | | | particularly if the engine is lugged at low revolutions |
| longevity of a car engine. With a forced lubrication | | | | per minute. Some engines have a gauge to show the |
| system that was invented by Frederick Lanchester, | | | | pressure at any particular time, but others just use a |
| the oil pump picks up the oil and forces it through the | | | | warning light to show if the pressure is too low. |
| drillings or oil galleries into the bearings that are the | | | | Either way, the sensor will usually be mounted close |
| most highly stressed, like the main bearings, or the | | | | to the engine's oil filter, by the oil pump. |
| big ends and camshaft bearings. Oil jets lubricate the | | | | Oil pressure is often higher if the engine is cold. This |
| cam lobes, cylinder walls, and other components. | | | | is because of the viscosity of the oil and also |
| Having the right amount of pressure will make sure | | | | increases in engine speed. Pressure will be at its |
| that the metal of the journal or rotating shaft and | | | | lowest when the car is hot and idling, and the |
| the metal of the bearing shell will never touch. This | | | | minimum oil pressure allowed by the manufacturer is |
| helps reduce wear to only the initial engine start up | | | | usually the case at this point. |
| and shut down. The rotation of the shaft, combined | | | | If pressure is too high, you could have a filter or oil |
| with the oil pressure will center the journal in its shell | | | | galley that is blocked or you might have the wrong |
| hydronamically. | | | | grade of oil. Some older gauges are labeled using the |
| As you see an increase in bearing clearance from | | | | term "druck" or "drucks". But newer model cars either |
| wearing and the declining in oil pump efficiency with | | | | don't have oil pressure gauges, or will instead have |
| age, the pressure will also decrease. After some | | | | status lights, or a oil pressure gauge labelled with a |
| time, it may be too low to protect the bearings, | | | | pictograph. |