What Causes Excessive Oil Pressure?

[DelMakayla]

Excessive oil pressure can be caused by a clogged oil fine filter, a blocked or improperly adjusted pressure relief valve, or excessive oil viscosity. The details are as follows: 1. Clogged oil fine filter: A dirty filter element in the oil fine filter can block the oil circuit, leading to excessive pressure in the main oil passage. Therefore, the oil fine filter should be cleaned regularly. 2. Excessive oil viscosity: The viscosity of oil is related to the engine temperature. When the temperature is too high, the viscosity decreases, and vice versa. If the oil viscosity exceeds the specified value, the flow resistance of the oil in the lubrication system increases, and the pressure rises accordingly. During a cold start, if the oil is too viscous and the flow resistance is too high, the oil pressure gauge will indicate excessive pressure. However, at this time, the lubrication of the main bearings, connecting rod bearings, and cylinder walls is insufficient. In such cases, the engine should idle for a few minutes to warm up to above 50°C before driving. Additionally, if the oil grade is improperly selected and the oil itself is too viscous, the oil pressure will also increase.

[DelColin]

Last time at the repair shop, the mechanic mentioned that excessive oil pressure is mostly caused by inappropriate oil viscosity. For example, using high-viscosity oil like 15W-40 in winter can easily cause issues, though it's less problematic in summer. Another possibility is a stuck pressure relief valve, which normally regulates pressure but fails if clogged by sludge. The most dangerous scenario is installing the wrong oil filter model—some aftermarket parts have bypass valves that simply won't open. I recall a friend's car whose oil pressure gauge maxed out, only to find the oil pump's pressure adjustment screw had been tampered with. Bottom line: if the dashboard warning light turns red, stop immediately—blown engine seals are costly to repair.

[LaJason]

As a veteran driver with 20 years of experience, I've encountered three instances of abnormal oil pressure. Besides the common issue of oil viscosity, special attention should be paid to pressure spikes during cold starts – it's often caused by a clogged crankcase ventilation valve. That component is located on the side of the engine; when blocked, exhaust gases can't escape, and crankcase pressure can shoot oil up to two meters high. Another time on the highway, the pressure gauge suddenly maxed out, but it turned out to be just a false alarm caused by water in the pressure sensor connector. Now during every oil change, I closely monitor the mechanic's work – the pressure relief valve near the oil pan must be thoroughly cleaned with carburetor cleaner. A word of caution: be careful with electrical modifications. There have been cases where installing fog lights caused voltage irregularities that affected sensors.

[SanAshley]

Last time I helped my neighbor check his old car with excessive oil pressure, I found several key points. First, check the oil dipstick—if it's over 3 cm above the upper limit, that's absolutely unacceptable. The oil cooler pipes in older cars are particularly prone to clogging; using an endoscope reveals black carbon deposits. The spring force value of the pressure regulator valve is crucial—some repair shops use substitute parts that simply can't open. Turbocharged cars require extra caution; a leaking intercooler can allow the air-fuel mixture to enter the crankcase. Here's a practical tip: when the engine is hot, unscrew the oil cap. Under normal conditions, it should slightly suck in air; if it blows out air, don't drive it.