How to Diagnose and Fix Low Engine Oil Pressure

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Pinpoint the cause of your oil issue and fix it fast
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Oil flows through your engine to keep all of the moving parts lubricated. Without that lubrication, your engine’s components will rub against one another and generate friction, which is not only bad for your engine’s health, but a potential fire risk. So, if your engine oil is low, you need to investigate it to solve the underlying problem. We’ll help you solve that problem here.

1

Add oil to your engine.

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  1. Like your windshield wiper fluid and gas, engine oil levels dissipate over time. If you haven’t change or refilled the oil lately, you’re likely just running low. This is a pretty mundane issue that’s easy enough to test and solve. Check the lid of the oil valve for the type of oil your engine needs (it should be something like 5W20 or 10w30). Purchase a quart of oil and pour it into the oil valve using a funnel. [1]
    • The Diagnosis: With a cold engine, pop the hood and locate the oil dipstick on the side of the engine. Pull the dipstick out, clean with a cloth, and reinsert it. Remove it once more to see where the oil reaches. If the level is low or says “add one quart,” you’re low.
    • Cost to Repair: A quart of oil shouldn’t run more than $5-10. Just make sure you’re using the right oil based on your manufacturer's recommendations!
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2

Change your oil.

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  1. If you haven’t driven the car in a few years, the oil likely went bad. Oil has an expiration date of 2-5 years, but it’s even lower if it’s been sitting in your engine for a while since temperature changes and debris in the oil lines can degrade the oil faster than if it were just in the original container. Either get an oil change at the mechanic or change the oil yourself . [2]
    • The Diagnosis: If it has been over 1-2 years since the vehicle was driven, it’s basically guaranteed this is the source of your oil pressure issues. If it’s been more than a month since you drove the car but less than a year, check the color of the oil. Old oil will be milky, hazy, and thick.
    • Cost to Repair: An oil change shouldn’t run more than $50-60. If you do the change yourself, you’ll save about $40.
3

Replace your oil pump.

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  1. The oil pump is responsible for pushing the oil through the filter, into the engine, and back through the filter. Without the pump firing, that oil will just sit still, which is basically the same as not having oil flow through part of your engine. See a mechanic to have them swap your busted pump out for a new one. [3]
    • The Diagnosis: The pump is likely the culprit if your engine oil levels aren’t low or you’ve refilled it recently but you still notice overheating. The car may make grinding noises and your oil pressure light is likely to go off.
    • Cost to Repair: This can range from $400-800 depending on how tough the pump is to access and what kind of car you drive.
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4

Get your pressure sensor repaired.

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  1. This involves some complex electrical work, so see a mechanic to have this sensor repaired and calibrated properly. The oil pressure sensor (or sending unit) is responsible for monitoring the flow of oil in your engine. When the levels are low or the oil pressure drops, the sensor is supposed to send a signal to your vehicle’s main computer that there’s an issue. But if the sensor dies, your engine’s control module will just assume the oil is low. [4]
    • The Diagnosis: If you keep seeing a “check engine oil” warning light but you’ve inspected everything and there’s nothing wrong with the oil or oil level, it’s likely the sensor. Your check engine light may come on as well alongside the oil light.
    • Cost to Repair: Expect to spend $100-400 depending on where your sensor is located and how hard it is to install.
5

Tap the oil gauge with your finger.

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  1. The oil pressure sensor monitors the oil level, but on older cars there’s a physical gauge that has to relay that information. If the gauge has failed for some reason, it may go to “E” or “empty” regardless of whatever the actual oil level is. Mechanical gauges can get stuck, so try tapping it. If that doesn’t work, see a mechanic. [5]
    • The Diagnosis: If absolutely nothing is wrong with the oil levels, your car is running fine, you don’t see an engine oil warning light but the gauge itself is still reading empty, the gauge is bad. On some vehicles, a “check gauges” light will pop on as well.
    • Cost to Repair: If the gauge itself really needs to be replaced, expect to spend about $100-130.
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6

Repair the leaky lines or gaskets.

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  1. Oil gaskets, valves, and lines can all leak, so see a mechanic to have your engine bay inspected for oil leaks. Your vehicle has a lot of moving parts and your engine generates a lot of heat. All of that leads to wear and tear on your oil system. If there’s a leak, the oil pressure will slowly dissipate until your oil is empty. [6]
    • The Diagnosis: Look for drips under the engine bay. If you spot a dark, oily substance, that’s oil. You’ve 100% got a leak somewhere. You may also see smoke when you drive, since the oil will burn away in the engine bay. You also likely have a leak if you find yourself refilling the oil multiple times a year.
    • Cost to Repair: It depends on where the leak is and how bad it is, but you’ll likely spend around $80-200.

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      Warnings

      • You cannot keep driving and ignore this problem. If you drive without oil, your engine will eventually fail, catch fire, or both. However, if you do have at least 15% of an oil tank left, go ahead and drive to the mechanic if you aren’t going to tackle this problem yourself. [7]
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      Expert Interview

      Thanks for reading our article! If you’d like to learn more about car maintenance and repair, check out our in-depth interview with Michael Dey .

      References

      1. ↑ https://www.consumerreports.org/cars/car-repair-maintenance/how-to-check-car-engine-oil-a7618306432/
      2. ↑ https://www.repairsmith.com/blog/does-motor-oil-expire/
      3. ↑ https://www.carsdirect.com/car-repair/common-oil-pump-failure-symptoms
      4. ↑ https://www.repairsmith.com/blog/engine-oil-pressure-sensor/
      5. ↑ https://blog.wika.us/knowhow/8-common-reasons-for-pressure-gauge-failure/?doing_wp_cron=1700691400.4062509536743164062500
      6. ↑ https://news.kixxoil.com/how-to-prevent-engine-oil-leaks/
      7. ↑ https://www.consumerreports.org/cars/car-maintenance/things-to-know-about-oil-changes-for-your-car-a9532249359/

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