Rick's Free Auto Repair Advice

What does it mean when my oil light is on?

When your oil light is on

There are two kinds of oil lights: an oil pressure light and an oil level light. Most vehicles only have an oil pressure light. Usually, only luxury cars have both. In those vehicles, the low oil level light usually tells you to check your oil level. In either case, if just the oil light is on, pull over immediately and check the oil level.

What the oil light means

Engines need at least 7-psi. of oil pressure to keep rotating metal parts from touching. When you start a cold engine, the oil light will go out as soon as pressure builds to around 7-psi. If the oil light comes on AFTER the engine has started, it means the only pressure has dropped below the minimum and that’s really bad. Driving with an oil light on can destroy your engine.

What are the possible causes of an oil light on?

You’ve run low on oil and the oil pump is sucking air

Check the oil dipstick and add oil ASAP if the level is below the minimum marking on your dipstick

The oil pressure sensor is defective

If you’ve checked the oil level and it’s fine, then the engine is running smoothly with no knocking sounds, the sensor may be defective. Have a shop test the actual oil pressure using a gauge.

The engine bearings are worn

If you neglect routine oil changes and allow internal engine parts to wear, the gaps between metal parts increase, making it harder for the oil pump to maintain the proper pressure. There’s no good fix for this problem except for a new engine or an engine rebuild. Any shop can test for worn bearings.

The oil pump relief valve is stuck

Most oil plumps have a relief valve to bleed off excess pressure. If the valve stick in the open position, it will constantly bleed off pressure, causing the oil light to stay on.

The oil pump is worn out

Oil pumps normally last the life of the vehicle. However, if you’ve neglected routine oil changes, the wear can damage the pump and prevent it from outputting the proper oil pressure.

What to do when your oil light comes on

Pullover immediately and shut off the engine.

Check the oil level on the dipstick

oil dipstick showing no oil

If it’s below the minimum markings, call roadside assistance or a friend to bring you more oil. Adding the wrong oil is better than running your engine with low or no oil. Do NOT continue to drive. You can destroy your engine, costing you thousands! If you can’t get someone to bring you oil, CALL A TOW TRUCK. A tow will be much cheaper than the cost to replace your engine.

©, 2021 Rick Muscoplat


Posted on by Rick Muscoplat

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