The oil pressure light on a Toyota FJ Cruiser.

Reasons why the oil pressure light turns on

In Automotive Diagnostics by HomeTowne Auto Repair & Tire

Over the course of using a vehicle, you may occasionally notice a dashboard light illuminate. 

Many people are familiar with the check engine light, but there’s another one that you should be aware of – the oil pressure light.

This light can appear for a few reasons. If it does turn on, there are some immediate actions you should take.

Oil pressure light on? Here’s what you should do.

You should avoid using your vehicle if your oil pressure warning light turns on. What if it appears when you’re driving? Pull over in a safe location. 

The oil level on an oil dipstick.

Then, check your oil. To learn how to do that, check out our “How to check your oil” article. If the oil level is good, don’t drive it and have it towed to a nearby auto repair shop. 

If the oil level is low, add oil and turn the vehicle on to see if the light goes out.  

What can cause the oil pressure warning the light to come on?

Low oil

Not having enough oil is one reason the light will illuminate. The oil pressure light is a lot of times going to be the same light that tells you that you’re low on oil. Low oil can be the result of an oil consumption problem or an oil leak. More information about the causes of oil leaks and the importance of addressing them can be found in this article we published.

Oil pressure switch on a Toyota Camry.

Bad switch

There’s a common problem with certain manufacturers where the oil pressure switch will just go bad. The switch is responsible for measuring the oil pressure and sending the signal to the dashboard. It’s possible that it may just need to be replaced.

Mechanical low oil pressure

Clogged ports and channels inside of the engine will cause low oil pressure. So, mechanically, low oil pressure will cause the light to come on. There’s a threshold. That car knows what the oil pressure should be at when idle, at wide open throttle, and at certain RPMs. The pressure is going to change. So, mechanically lower pressure than the specifications will cause the light to turn on.

How we address an oil pressure warning light

If a vehicle comes in with its oil pressure light on, we first start by correcting the oil level. It’s an easy, simple thing that a lot of people forget.

The second step is testing our switch and making sure it’s working. If it is, then we measure the mechanical oil pressure. We, basically, figure out what needs to be fixed.

Our findings will determine what the repair is going to be. The most common problem is sludge. Sludge buildup on these vehicles will lead to low oil pressure, because it blocks the passages. In that situation, we try to restore rather than repair.

Two GM engines we worked on had low oil pressure. One of the vehicles had mechanically low oil pressure and its low oil pressure light was on. We ran a cleaner through the engine and did some restore with transmission fluid. It cleared up the passages and the driver got his oil pressure back.

The other vehicle had a timing code that kept coming back from the variable valve timing system. A BG restoration kit was used, and the code never came back. This van always had good oil pressure, but it had a phaser that operated from oil pressure and was clogged.

HomeTowne Auto Repair & Tire is an authorized Michelin and BFGoodrich tire dealer located in Woodbridge, Virginia. Automotive repair services are performed on all makes and models, including oil changes, brakes, alignments, inspections, and computer engine diagnostics.