What causes low oil pressure?

6 Most common causes of low oil pressure

The oil warning light in your dash comes on when your engine has low oil pressure, below 7-psi. Here are some common causes of low pressure.

A faulty oil pressure sensor can cause a false pressure warning

An oil pressure sensor is built with a diaphragm and electrical contacts. Over time, the diaphragm can degrade and leak, causing the sensor to report a false warning when the pressure is actually within specs.

To test for a faulty oil pressure sensor, either replace the sensor with a new unit or install a mechanical oil pressure gauge in place of the sensor to determine if the sensor it reporting accurately.

A Low oil level can cause the oil light to come on

An engine circulates oil throughout the engine and it drains back to the oil pan to be recirculated again. When your engine is low on oil due to oil consumption or an oil leak, the low oil level starves the oil pump, causing the oil light to come on. If your oil light comes on, immediately check the oil level on the dipstick and add oil if it measures low.

A stuck oil pressure relief valve can cause an oil warning light

Most oil pumps have a pressure relief valve to bleed off excess pressure at higher RPMS. If the pressure relief valve sticks, it will constantly bleed off pressure, causing the oil light to come on.

Sludge in the oil pan can clog the pick up screen

Sludge in an engine can clog the oil pump pickup screen so it can’t pump oil

If you’ve neglected oil changes and developed a sludge problem in the oil pan, the sludge buildup can restrict the oil pickup screen, causing oil starvation and an oil warning light. Cleaning the oil pickup can sometimes solve the problem.

Worn engine bearings can cause an oil light

In order to produce pressure you must have a restriction. The tight clearances in crankshaft and camshaft bearings provide the restriction to flow. However, when bearings wear out due to oil change neglect, the clearances widen, causing a  an oil warning light.

A clogged or damaged oil filter can cause an oil light

Many oil filters contain a bypass valve to keep

A clogged oil filter can’t filter oil

oil flowing around the filtration element when it gets clogged. If your oil filter has a faulty bypass valve, it will starve the oil pump and cause a low oil pressure situation.

Symptoms of low oil pressure

Oil light on
Clunking noise from the engine
Burned oil smell due to engine overheating
Poor engine performance
Engine overheating

©, 2020 Rick Muscoplat