What Are the Causes of Insufficient Oil Pressure?
3 Answers
The causes of insufficient oil pressure include the following points: 1. Insufficient oil quantity in the oil pan. When the oil quantity is insufficient, the oil pump's pumping capacity decreases, and it may even suck in air. The oil should be replenished according to the specified amount. If the insufficient oil is caused by oil burning or leakage, the issues of oil burning or leakage should also be addressed. 2. The oil quality does not meet the requirements. Different engine models require different grades of oil, and even the same engine model may use different brands of oil in different seasons. Using the wrong oil often leads to issues such as excessively thin oil viscosity and insufficient lubrication. Always use oil as specified. 3. Fuel or water mixing into the oil. If fuel mixes into the oil, it will dilute the oil; if water mixes into the oil, it will cause the oil to emulsify and deteriorate. Both scenarios reduce the oil's lubrication effectiveness. The oil must be replaced, and the causes of fuel or water mixing into the oil should be identified and resolved. 4. Excessive oil temperature. When the cooling system has severe scaling, poor heat dissipation, or prolonged overload operation leading to high engine temperatures, the oil may become thin. If the clearance between the cylinder liner and piston is too large, high-temperature gas from the cylinder can enter the crankcase, raising the oil temperature and thinning it, making it easier to leak from the friction pair's clearance. 5. Clogged oil filter screen or air leakage in the oil intake line. When the oil strainer screen is clogged, the oil pump cannot draw in enough oil. If the oil intake pipe has cracks, the gasket is uneven or not tightened, or the joint surface between the pump body and the engine block is uneven or the gasket is damaged (as in single-cylinder diesel engines), the oil pump may suck in air. These issues can all lead to insufficient oil pressure.
I remember my car had insufficient oil pressure before, which really gave me a scare. That time during a cold start, the dashboard warning light suddenly came on, and I immediately pulled over to check. Actually, insufficient oil pressure is quite common, mainly due to low oil level or oil that's too thin. Later, I found out it was caused by a clogged oil filter restricting flow, and another time it was due to severe wear on the oil pump. If the bearing clearances inside the engine are too large, it can also prevent oil pressure from building up. A faulty pressure relief valve is even more troublesome, directly causing abnormal pressure. I recommend regularly checking the oil dipstick, using oil with the right viscosity, and changing the oil every 5,000 kilometers for maintenance. If you encounter an oil pressure warning on the road, don't push your luck—shut off the engine immediately and inspect it. Otherwise, engine seizure and major repairs could cost you a fortune.
We often encounter insufficient oil pressure issues in the repair shop, with several key causes: insufficient oil quantity is the most fundamental reason, as many vehicle owners forget to regularly check the oil pan fluid level; oil pump wear can lead to reduced oil supply capacity, commonly seen in high-mileage vehicles; clogged oil filters obstruct oil flow, which is easily overlooked; inappropriate oil viscosity or dilution due to deterioration can also affect pressure performance. Excessive engine bearing clearance may cause oil leakage, naturally preventing pressure buildup. A failed pressure relief valve spring or stuck valve body can further lead to system imbalance. It is recommended to check the oil condition monthly, replace the oil and oil filter according to the manufacturer's specified mileage, and immediately inspect if abnormal metal friction sounds are heard.
