Why is the oil pressure lamp on?

Many drivers are faced with this situation,When the lamp on the instrument panel of the machine after starting the engine or turning it off completely, the oil pressure level is lit. Understand the reason for this is quite problematic. And this is not surprising: as practice shows, there are many reasons why the oil pressure lamp is on. With complete certainty, it can only be asserted that something has gone wrong in the vehicle.

Main reasons

The minimum oil level. To date, this reason is considered one of the most common. With regular use of the vehicle, it is recommended to carefully monitor the oil level, to try to notice the various stains on the motor casing. Any, even the smallest oil stains under the machine are sufficient grounds for testing the oil system.
The use of bad filters. Some volume of oil should always remain in the filter, despite the stop of the power unit. This is required in order that the effect of an "oil starvation of the engine" is not formed. As practice shows, many low-quality filters do not retain oil, so it flows into the crankcase without any problems. Cope with this situation can only be replaced by a better filter.
Malfunction of wiring. Very often, the oil pressure lamp burns for a long time because of wiring problems. It is located on the panel and connected to the sensor via a wire. If the oil pressure drops below a certain mark, the sensor closes the light bulb to "ground". When the pressure becomes normal, the contacts are opened - the lamp goes out. However, if the sensor itself is broken, the light bulb will not turn off. In this situation, you need to conduct a thorough diagnosis, replace the wiring, as well as parts that are out of order.
Damage to the pressure relief valve. If the pressure level is minimum, the operating pressure reducing valve will be located in the closed position. If it hangs or jams in an open position, the system does not generate the required pressure, respectively, the bulb will constantly be lit.
The mesh of the pump was hammered. It is this part that is responsible for the effective protection of the pump, as well as the power unit from the penetration of all kinds of garbage on various surfaces. Hard chips, dirt, dust and other objects all have a negative impact on the surface of numerous parts. If the oil is clean, without all kinds of dirt, then it easily passes through the mesh. At this point, the sensor is set "in a quiet state", which confirms the normal functioning of the motor. However, when the oil is contaminated and moves poorly through the filter, it is not possible to provide the required pressure. To solve this problem, it is necessary to replace the oil pan.
Oil pump failure. If this device can not guarantee the pressure necessary for high-quality lubrication, the contacts are closed, respectively, the bulb will constantly signal to the driver that there is a serious enough malfunction in his vehicle.

If the pressure bulb burns dimly, then it is worth checking the wiring or replacing the bulb itself.

About the oil pressure in the machine can be found from the article What is the oil pressure.