Oil Pressure Low at Idle – Common Causes & How to Fix

If you're experiencing low oil pressure at idle, don't panic! Here are some of the most common causes and how to fix them.

Low Oil Pressure At Idle

The car’s oil pressure gauge is needed to show you whether it is running too low, too high or just right. If the oil pressure starts to run low, it can lead to engine damage. That’s why you need to know why the oil pressure is low at idle, and fix it quickly.

In this guide, I look at the most common causes. I will also show you how to repair each of these problems. 

Causes of Low Oil Pressure at Idle

Most commonly, low oil pressure means that the oil level is low, especially when it happens at idle. It could also mean that the oil quality is poor, you have a clogged oil filter, the oil pump is defective, the oil pressure gauge could be faulty, or you might be using the wrong grade of oil for your car or the weather. 

1. Low Oil

If the oil level dips too low, it can cause a change in pressure when the engine is idling. The pump can’t work with the right amount of oil when it gets too low. With this issue, you might also notice the oil pressure dips during turns at higher speeds since the oil is moving from side to side, away from the sensors.

Low oil levels can be a simple oversight, while other times, it can be due to a mechanical problem. You need to know what’s causing it if you want to fix it. 

RELATED: How to Check Your Car’s Engine Oil

2. Poor Oil Quality

If you hadn’t changed the oil in the engine when you were supposed to, it could affect the pressure. As the oil becomes contaminated and dirty, it loses many of its original properties. 

The oil structure changes, leading to a loss of pressure. Its efficacy will also diminish, and it won’t be able to clean and protect the engine the way it should. 

3. Defective Oil Pump

The oil pump is a necessary component that keeps engine oil circulating in the system. When it fails, it can no longer pump the oil through the engine.

The oil indicator can start to flash, showing that the pump has gone bad. When this happens, it’s important to have it checked immediately before engine damage occurs. 

RELATED: 4 Symptoms of a Bad Oil Pump (& Replacement Cost)

4. Clogged oil filter

If you have not changed the oil filter for a long time, it can actually be clogged with sludge and it will reduce the flow and lead to low oil pressure in the engine. Replacing an oil filter is often very simple, and you should always replace the oil filter when performing an oil change on your car.

READ MORE: 5 Signs of a Bad or Clogged Oil Filter (& Replacement Cost)

5. Faulty Pressure Gauge

If you notice low oil pressure occurring at idle, the pressure gauge itself might be faulty. This can occur right after an oil change until the system falls back in line and registers the new viscosity. 

However, if it goes beyond that, you need to have the gauge checked and the electrical system looked at. It could be another issue leading to a faulty reading. 

6. Wrong Oil Grade

If you used the wrong type of oil in the engine during the last change, it could cause pressure problems. While some engines can use multiple grades of engine oil, there are a few that require a very specific formulation. 

If the oil is too thin or thick, it won’t flow through the engine properly. Plus, the motor won’t get the lubrication it needs. 

READ MORE: 0w20 vs. 5w20 vs. 5w30 – Oil Viscosity Explained

7. Damaged Engine

The worst-case scenario is that the engine itself is damaged. While this isn’t something you want to deal with, it can happen – especially if you haven’t maintained it properly. 

If all of the other situations don’t seem to be causing the problem, it’s time to examine what other symptoms the motor is experiencing. You can read the trouble codes, evaluate the performance and watch the fuel economy to get a better picture of what’s going on inside the motor. 

RELATED: How to Tell if Engine is Damaged From No Oil?

How to Repair Low Oil Pressure at Idle

1. Add More Oil

If the oil level in the engine is low, the only solution is to add the right amount. Use the oil dipstick to monitor where it is currently at.

If you notice that it’s too far down on the dipstick, it’s time to add more. Make sure that the oil viscosity matches what’s in there and that the quality is in good shape. You don’t want to add an abundance of fresh oil to dirty oil, as this simply degrades what you are adding. 

2. Perform Oil & Oil filter Change

If the engine oil is contaminated and dirty, the oil pressure might not be accurate because the viscosity changes. When it comes time to change the oil, go ahead and perform this vital maintenance step.

After the oil change, you should notice that the pressure regulates better. If not, the problem could be something else on this list. However, this is one of the cheaper fixes you can work with, so it’s best to start here. 

READ MORE: How to Change the Oil in Your Car (5 Easy Steps)

3. Replace Oil Pump

If the oil pump is bad, your only option is to replace it. However, this repair can have varying costs, depending on what type of vehicle you drive.

On average, an oil pump replacement might cost $350 to $2,000. Considering most of this cost is the labor involved, you could save some money if you can do the job yourself. 

4. Repair The Pressure Gauge

If the gauge is erratic and unpredictable, there could be an electrical problem or sensor issue. This would be especially true if you aren’t noticing engine performance issues.

To repair the gauge, you must first determine what part is failing. It could be the gauge itself or one of the sensors, both of which require professional diagnostics to determine. 

5. Use The Right Oil

If you think that the wrong oil viscosity was used in the engine, you need to replace it. Start by looking in the owner’s manual to determine exactly what you should have used. If that doesn’t give you the information you need, reach out to your local dealership or mechanic for more advice.

Once you know what oil to use, it’s time to change it. Don’t forget to also change the oil filter to ensure none of the old fluid remains in the system. 

RELATED: High Oil Pressure: Main Causes & Symptoms (How to Fix It)

6. Have The Engine Fixed

There are some engine issues that could be fixed. However, if the motor is severely damaged, you are looking at some hefty bills to repair it. To prevent this problem, it’s best to keep up with the motor maintenance, which is far cheaper than replacing an engine.

With that said, you have several options when it comes to replacing an engine. The cheapest is normally to have a used engine put in. These engines can be found at the salvage yard but normally don’t have any guarantees. You can also have the engine rebuilt. If you choose this option, the mechanic will dismantle your motor and rebuild it with better parts for smoother operation. 

There’s also the option to get a remanufactured engine. Your old engine is removed and replaced with one that has already been restored with newer parts. With this type of engine, you often get some type of guarantee on the engine and labor. However, the most reliable way to fix the problem is to get a new crate engine installed. This new motor is the most expensive option, often costing $4,000 to $10,000 or more, depending on the type of vehicle you drive.

READ MORE: Low Oil Pressure: Symptoms & Causes (& How to Fix it)

Magnus Sellén
Written by:

Magnus is the owner and main author of Mechanicbase. He has been working as a car mechanic for over 10 years, and the majority of them specialized in advanced car diagnostics and troubleshooting. Certified Automotive Diagnostic Technician.

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