Why does the oil light come on when parked but not when driving?

[FernandoMarie]

When idling while parked, the oil pressure may be low. During driving, the engine speed is higher. It is recommended to check as soon as possible whether the low oil pressure is caused by an issue with the oil pump or excessive bearing clearance. The reasons for the car oil light coming on are as follows: 1. Excessive oil viscosity: The viscosity of the oil is closely related to its quality. The higher the viscosity, the better the oil's resistance to high temperatures, and vice versa. However, higher viscosity is not always better; the oil grade should match the engine specifications. 2. Pressure relief valve clogged or improperly adjusted: To prevent excessive oil pressure in the lubrication system, which increases engine power consumption and causes leaks at sealed connections in the oil circuit, a pressure relief valve is installed in the main oil passage or oil pump. Its function is to limit the oil pressure in the lubrication system to within the specified value. A faulty pressure relief valve can lead to abnormal oil pressure, causing the oil light to illuminate.