The oil light will turn on when the engine does not have enough oil pressure. There is a pressure sensor located inside the engine block. When the sensor notices a drop in pressure, the oil light will turn on to notify the driver.
An engine must maintain consistent oil pressure so that all the moving internal components remain properly lubricated. When the oil pressure drops, the internal parts will no longer receive proper lubrication, which will lead to engine failure.
Causes of oil pressure loss
- A faulty oil pump - the pump circulates the oil inside of the engine. The flow produced by the pump creates oil pressure. When the pump fails, the oil will no longer lubricate all the necessary components, which can result in an engine knock, damaged crankshaft or burnt piston rings
- Worn connecting-rod bearings - connecting-rods have a metal bearing that allow them to move along an engine's crankshaft. When the bearings wear out, the clearance between the crankshaft and connecting-rods change. This change lowers the oil pressure inside of the engine
- A clogged oil filter - oil has to pass through a filter before entering the pump. If the filter is clogged, the engine will be starved of oil and air will also enter into the pump. When air enters the pump, the engines loses oil pressure, which then starves the internal components of the engine