1. Oil Pump Failure: Low oil pressure could be a sign of a failing oil pump. As the oil pump becomes worn or damaged, it may not be able to generate and maintain the necessary oil pressure.
2. Faulty Oil Pressure Relief Valve: The oil pressure relief valve prevents oil pressure from becoming too high. However, if it malfunctions and gets stuck open, it can leak off too much oil and consequently lower the oil pressure.
3. Excessive Bearing Clearance: When bearing clearances become too loose due to wear, more oil can pass through the bearings, reducing oil pressure. This commonly occurs with high-mileage engines.
4. Oil Viscosity Issues: Using oil with an inappropriate viscosity can affect oil pressure. Too thick an oil may not flow sufficiently in warm conditions, leading to lower pressure. On the other hand, too thin an oil might not provide enough resistance at higher temperatures and thus result in reduced pressure.
5. Oil Leaks: If there's a significant oil leak somewhere in the engine or other components connected to the oil system, it can result in the drop in oil pressure. Check for oil leaks around the oil pan, seals, and other potential leak points.
6. Clogged Oil Filter: An excessively dirty or obstructed oil filter can impede oil flow and cause a pressure drop.
7. Oil Sludge and Debris: Accumulation of sludge and debris inside the oil passageways could partially block them, hindering proper oil flow and consequently dropping oil pressure.
Since a sudden significant drop in oil pressure while driving can have serious consequences for the engine, including potential damage to bearings or other components, it's best to have it examined by a qualified mechanic as soon as possible to identify the exact cause and perform necessary repairs/service.
