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So you looked down at your dashboard the other day and saw your oil pressure gauge is through the roof. You thought, Great, my engine is extra lubricated! I have bad news for you: you might be dealing with a faulty gauge which could in turn put your entire engine at risk. There’s a simple test to find out.

Get in your car without the engine running. Then turn the key to the “on/run” position, but not all the way to the “start” position. If your electronics turn on, but your engine doesn’t turn over, you’re in the “ignition” position.

Once you turn the ignition on, all of your gauges should run a check. They will sweep on, then fall back to an accurate measurement. With the engine off, your oil pressure gauge should fall to zero PSI. If it didn’t the “sending unit” which measures the oil pressure in your engine is likely faulty.

A car owner checking their engine oil level with a dipstick
Checking your oil level with the dipstick can give you more information | Uzhursky via iStockPhoto

Most oil pressure gauges run from zero PSI to around 80 PSI. Some show 10s of PSI, with “0” “4” and “8” positions. Most engines will run around 40 or 50 PSI. Any reading below 20 PSI is dangerous for your engine.

This “sending unit” is threaded into your high pressure oil lines. If you’re a DIYer, you may find it’s a cheap part and easy to replace yourself. Simply price it out online and find a video of a mechanic swapping it. On the other hand, if you are bringing your car in for any other services, swapping the sending unit should be a cheap add-on.

What in the world is an oil pressure sending unit? It measures PSI, similar to a tire pressure gauge. But it is plumbed into your oil system, just “down stream” of your oil pump. This way, if your filter gets clogged or your oil level gets dangerously low, you should see the PSI drop so you know there’s a problem.

Next, learn what the E and F on your fuel gauge truly mean.

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Staff Writer

Henry Cesari

Henry Cesari joined MotorBiscuit in 2021 and brings his deep interest in vintage cars, trucks, and motorcycles to the site. Having restored his first classic car at just 16 years old, Henry has wrenched on everything from overland campers to Japanese motorcycles and even pre-war Bugattis. Henry is also an avid attendee at local car shows and genuinely enjoys connecting with fellow auto enthusiasts.

Henry earned a Bachelor’s in Anthropology and English from the University of Vermont. He has since incorporated his love of the written word with his admiration of classic cars. While Henry is interested in vintage cars, he believes the golden age of cars is yet to come. He is confident journalists will play an important role in this revolution by exposing the industry as it is now and envisioning its possible future.