Informational Guide

What Causes Low Oil Pressure?

Not only will we show you how to check oil pressure, but we will discuss the signs of low pressure and show you how to repair it.

Your vehicle must have the right amount of oil pressure to run properly.

Not only will we show you how to check oil pressure, but we will discuss the signs of low pressure and show you how to repair it.

If you notice any of these symptoms, you will want to know how to check the oil pressure in a car before any further damage occurs.

Warning light turns on

Your vehicle’s warning light is the first sign that something is wrong. This light connects to a sensor in charge of monitoring oil levels. When the pressure becomes too low, your light should alert you. When you see this indicator, don’t mess around. Have your vehicle serviced immediately.

Burning oil odor

Any time that you smell oil burning, you take immediate action. It could be a sign of an oil leak that is dripping on engine components. Allow the engine to cool down and then check the oil levels. If it is low, you can top it off, but you will want to have the pressure issue or leakage looked at.

Deep knocking or thumping sound

As your vehicle runs without the right amount of oil pressure, knocking sounds occur. Sounds come from the under-lubricated valve train and camshafts, which eventually causes larger issues. Don't just throw in the best oil additive for engine knock, but resolve to find the condition causing the noise.

Car Issues when at Idle

Whenever the engine doesn’t receive the amount of oil it needs, it can lead to performance issues. Most of the time, these performance issues will reveal themselves while idling. Pay attention to the sound and feel of your vehicle while driving at low speeds and idling.

car dashboard

Common Causes of Low Engine Pressure

Low level of engine oil

The number one reason that you are experiencing low oil pressure is because there isn’t enough oil. With regular checks and tune-ups, this shouldn’t be a problem unless there is a leak in the system. It’s preferable to check your oil levels at least once a month.

Engine wear

If your oil level is where it should be, the problem might be engine wear instead. Worn engine bearings in high-mileage motors often cause trouble with oil pressure because the flow is restricted. When this occurs, you most likely need an engine rebuild or replacement.

Damaged oil pressure gauge

It’s not hard to learn how to check the oil pressure gauge. If your warning light comes on, but the levels are correct, you want to check for a defective sending unit. This might also require you to replace the oil pressure sensor or the oil pump. It’s difficult to figure out how to check oil pressure without a gauge, so don’t hesitate to get it checked out.

Dirty oil filter

Oil is a lubricant that must reach the engine. However, the oil filter stands in the way. When working properly, it allows just the right amount of oil through. If it becomes clogged and the bypass valve doesn’t work, your engine doesn’t receive the oil it needs and starts to suffer.

Oil viscosity

When you choose your motor oil, you must choose the right viscosity. Motor oil viscosity is determined by the type of vehicle you drive and the motor it uses. When you choose one with a higher viscosity than what's called for, the oil could become too thick to properly move through the system.

Worn Out Oil Pump

The vehicle's oil pump moves the oil through the system. If the oil pump fails to work correctly, it might not supply the engine with the lubricant it needs. Sometimes the pump fails because of poor installation or faulty maintenance, but it should never be overlooked, or you could face serious engine damage.

Engine overheating

As the engine overheats, the oil also gets hotter. This causes the oil to get thinner than intended. Just like thick oil can create problems, so can thinner viscosity oil. The lubricant might not properly work around the components and prevent engine damage from occurring.

How to Diagnose Low Oil Pressure

If you want to learn how to check oil pressure in a car, all you need to do is look at the pressure gauge. If you receive a zero reading, there is something significantly wrong. Either no oil is being pumped into the system, or your gauge is faulty.

As you learn how to check low oil pressure and notice a low reading on the gauge, it could be a leak or worn out part. You shouldn’t run your engine any longer with low or non-existent pressure unless you want to deal with expensive engine repairs. However, you might also notice a consistently high oil pressure reading. This can also indicate trouble with your oil filter or a blockage in a delivery line.

Once you know how to check oil pressure manually and notice a problem, you want to take action. First, check the oil level to make sure it doesn’t require a top-off. You should also check the system for leaks. If you need professional help, a mechanic can run further tests.

red car

Troubleshoot Low Oil Pressure

You want to know how to check the pressure and also how to check if an oil pressure sensor is bad. Follow these steps if you plan to do it on your own.

  1. 1
    Start your vehicle and leave it on level ground.
  2. 2
    Observe the oil pressure gauge.
  3. 3
    Check the engine oil level with the dipstick. Fill up if needed.
  4. 4
    Remove the oil pressure switch and use a manual gauge with the engine to check the readings. You should see between 25 and 45 pounds.
  5. 5
    The oil pump screen could be contaminated. Drop the engine oil pan to clean the screen. You may also need to replace the oil pump.

Aside from these steps, you are looking at a major problem causing your low oil pressure, such as a faulty engine bearing or oil pressure relief valve.

People Also Ask (FAQs)

Can you drive a car with low oil pressure?

You should never drive your vehicle with low oil pressure, or you could cause serious engine damage. Instead, learn how to check oil pressure on a car and resolve the problem.

Can I just add new oil to my car?

While adding a little oil to your car when the levels are low is good, it can’t be all you do. Remember to perform regular oil changes to keep your engine running its best.

How long can an engine run with low oil?

The effects of running a vehicle without the right amount of oil are disastrous to car engines. Without any oil, an engine would run for a few minutes before completely failing.

What causes diesel engines to run at a low oil pressure?

It doesn't matter whether you have a gasoline or diesel engine; the causes of low oil pressure remain the same. Check the amount of oil in the system, look for leaks, and rule out any mechanical issues.


What causes low oil pressure? We've reviewed the top concerns and shown you how to resolve the problems. Whatever you do, don't drive your vehicle with low oil pressure, or you could ruin the engine.