What Causes the Oil Light to Illuminate When There Is Oil?
2 Answers
The following are specific reasons why the oil light may illuminate even when there is oil: 1. False fault alarm: A false fault alarm mainly refers to a malfunction of the oil pressure sensor—the oil pressure sending unit. This means the sensor itself, which is designed to monitor the engine oil pressure, fails. 2. Engine sludge: Engine sludge can sometimes be related to the oil light illuminating. It's quite straightforward: large impurities formed by engine sludge can easily clog the oil pump screen (oil pickup) in the oil pan, leading to low oil pressure. Additionally, engine sludge can cause the oil to degrade or change in viscosity. If the oil viscosity becomes too high, it may also trigger the oil light alarm.
With years of experience in the automotive repair field, when encountering the situation where the oil light is on but there is oil, the most common causes are insufficient oil pressure or a faulty sensor. The oil system doesn't just rely on the amount of oil; it also depends on pressure to lubricate engine components. If the oil pump is aging or the filter is clogged, the pressure won't rise, and the warning light will come on. I recommend first stopping to check the dipstick: if the oil level is fine, try starting the engine and listen for the oil pump's operation sound. Normally, it should be a low hum, but an abnormal sound could indicate a faulty pump or a blocked oil passage. Secondly, the sensor might be faulty and giving false readings, or it could be affected by electrical interference, such as aging or short-circuited wiring. Don't ignore this issue—continuing to drive could damage the engine bearings. The safe approach is to stop immediately and have a professional shop use tools to measure the oil pressure for a diagnosis. Avoid driving further to prevent major damage. Regular maintenance, including frequent oil and filter changes, can help prevent such issues.
