An oil pressure sensor is a device that measures the pressure at which the oil pump is pumping engine oil. Most oil pumps operate in the 20 to 40 pounds per square inch range. If the oil pressure drops below this level, permanent engine damage can occur.
1. Electrical Sensors
The oil pressure sensor on some cars sends signals to an oil pressure gauge on the dashboard electrically. The voltage level of this signal will pertain to a given level of pressure. This type of combination is mostly found on higher performance and more expensive cars.
Another type of electronic oil pressure sensor only sends a signal which turns on a light on the dashboard. This indicates problems in the engine’s lubrication system. This type of system is colloquially called an idiot light. These types of oil pressure sensors, also called oil pressure sending units are called electrical oil pressure sensors, and are the most accurate when properly calibrated.
2. Mechanical Sensors
The other type of oil pressure sensor is the mechanical type. This type of pressure sensor has a diaphragm against which the pressure of the oil operates against. When the oil pressure pushes against and deflects the diaphragm, it moves an indicating needle the corresponding amount on a gauge. If the needle doesn’t move when you have the engine running, you either have no or very low oil pressure.
If your car is equipped with an indicating light, you can purchase a gauge set with a new oil pressure sensor feeding a gauge. This gauge can be mounted anywhere that you can see it easily while driving. Normally, by the time an indicating light is turned on, irreparable damage to your engine has already occurred. If your car isn’t equipped with an oil pressure gauge, it is highly recommended you upgrade to one.
