What are the causes of low engine oil pressure?

[VanOmar]

Here are the reasons for low engine oil pressure: 1. Insufficient oil in the oil pan; the oil viscosity is too low. 2. The spring tension of the pressure relief valve is insufficient or improperly adjusted. 3. Severe oil leakage in the lubrication system pipeline; the oil fine filter is damaged and leaking. 4. The oil pump is excessively worn or faulty. 5. The oil pressure gauge or sensor is malfunctioning. 6. Excessive clearance in mating parts such as bearings, connecting rod bearings, and camshaft bushings. Here are the situations of low engine oil pressure: 1. Dirty or viscous oil, causing the oil pump to fail to suck in or pump out oil, resulting in low or no oil pressure. 2. The oil becomes too thin and leaks from the friction pair gaps in the engine, causing low oil pressure. 3. Oil pipe leakage, oil pump damage, or excessive wear of its components, such as excessive clearance between the crankshaft and bearing shells, malfunction of the pressure relief valve or relief valve due to a weak spring or damaged steel ball, all reduce the amount of oil sucked in and pumped out, leading to low or no oil pressure. 4. Malfunction of the oil pressure sensor, pressure gauge, or circuit results in low oil pressure.

[DiTalia]

I was also startled when the oil light on my car's dashboard came on the other day. The most common issue is insufficient oil—remember to check the dipstick level on flat ground after turning off the engine for ten minutes. If it's below the minimum mark, top it up with the same type of oil immediately. If the oil level is normal, it's likely an issue with the oil pump—either wear in the pump body causing pressure loss or sludge clogging the oil pickup screen can lead to insufficient pressure. Another possibility is a clogged radiator restricting oil flow or excessive clearance in the crankshaft bearings causing oil to leak too quickly. Last time, my friend’s car had the oil filter installed backward, leading to pressure buildup—it took a while to figure that out. In such cases, it’s best to visit a repair shop to read the fault codes, as DIY fixes can be too risky.

[CamilleRose]

I've handled quite a few cases of low oil pressure. For older vehicles, the first common issue is insufficient oil viscosity - either from using lower-grade oil or fuel dilution thinning the oil. Another frequent culprit is sludge clogging the oil pickup tube screen, like boba pearls blocking a straw. Once I saw a customer's car with the oil pump relief valve stuck open, causing all the oil to just circulate through the bypass. Some modified cars with tuned ECUs but unupgraded lubrication systems can experience oil starvation at high RPMs when oil gets flung onto cylinder walls. While faulty oil pressure sensors giving false warnings are actually quite common, it's always better to have false alarms than actual failures.

[PiperRose]

Low pressure at startup may be due to winter oil being too viscous for the pump to circulate. If the warning persists after warming up, check these five points: oil level, viscosity, pump, filter, and bearing clearance. Last year, while helping a neighbor troubleshoot, we found the issue was an oil leak caused by a loosely tightened oil filter during maintenance. For recently overhauled engines, improperly adjusted bearing clearances are often the culprit. If the cause remains elusive, replace the sensor with a mechanical pressure gauge to verify readings. By the way, turbocharged vehicles suffer from oil dilution issues far more severely than naturally aspirated engines.

[LydiaLynn]

Insufficient oil pressure is actually the lubrication system crying for help. Low oil level in the oil pan is the most basic mistake; emulsified oil resembling lumpy milk tea completely loses its lubricity; while internal wear in the oil pump allows pressure to leak through side clearances. When crankshaft bearings develop grooves, oil drains away like floodwater. The strangest case I've seen was oil leakage from the balance shaft chain tensioner, spraying oil right into the timing cover. If the warning light comes on when hot but not when cold, it's likely due to oil thinning from high temperatures or excessive bearing clearance. Checking residual oil viscosity during each maintenance can prevent many issues.