We all know that motor oil is the lifeblood of the engine. It lubricates the reciprocating internal engine parts to offer optimal operation. It keeps the engine parts well-lubricated and protected.
There’s an internal engine part called an oil pump that helps to circulate the oil to every nook and cranny part of the engine. As a result, the engine oil will build pressure. This oil pressure is built when the motor oil is flowing through the oil galleries.
If there’s low oil pressure, it will cause accelerated wear if ignored and cause severe engine breakdown. This is why most motorists worry when they notice low oil pressure at idle only or when driving.
Here, we’ll explain the causes and how to fix low oil pressure at idle. But before we proceed, kindly check low oil pressure symptoms for a better understanding.
What Is Normal Oil Pressure At Idle?
Oil pressure is a vital indicator in car engines you need to consider. However, it’s going to vary depending on some factors: types of engines and temperature.
To know the exact pressure of oil at idle, first, let’s have an overview of the oil pressure.
What is the oil pressure?
Automotive engine oils operate in the form of a circulating system. The oil will be injected by the pump into the engine, then flow into the tank, then continue to be sucked up through the filter and sprayed into the engine.
Oil pressure is created by the pump pumping oil into the vehicle’s engine system. When the engine operates, the normal oil pressure is usually in the range of 25-65 PSI (depending on the vehicle model).
The normal oil pressure always remains stable within this level. If the oil pressure suddenly rises or falls abnormally low, it is a sign that the lubrication system is having problems.
Cars are equipped with an oil pressure sensor. If it detects that the oil pressure is too high or too low, the sensor will transmit a signal. And the ECU will turn on the lubricating oil pressure warning light to notify the driver.
When you see that the car has abnormally low or high oil pressure, it should be checked as soon as possible. Because the lubrication system malfunction will greatly affect the engine.
What should oil pressure be at idle?
To ensure your car engine operates with the best performance. Automakers recommend that the oil pressure should always be above 20 PSI (pounds per square inch) when idling.
However, corresponding to each type of vehicle, we will have different pressure levels:
- Truck: 20-30 PSI at idle
- Car: 25-35 PSI at idle
Most carmakers suggest that oil pressure should be around 30 PSI when running idle and about 60 PSI when the engine is running at higher speeds.
If you notice that the oil pressure is low than 20 PSI, you should check as soon as possible.
As we all know, engine oil not only helps the moving parts of the engine operate smoothly but also helps to cool them. If the pressure is too low, the engine will not be properly cooled, and it can cause serious consequences.
This difference in the oil pressure will happen as the oil’s viscosity thins due to heat. Most vehicle engines have an oil pump.
The principle is to increase pressure with speed, so the engine spins higher and the result is the oil pressure increases.
This function makes sure that parts in your engine have enough lubrication as they move faster and start generating more heat.
When your car runs idle, you don’t need the high oil pressure. 20-25 PSI is sufficient for most engines. You just ensure that the pressure will go up when your car increases its speed.
Symptoms of Low Oil Pressure at Idle
Recognizing the symptoms of low oil pressure at idle is crucial for taking timely action to prevent engine damage. Common signs include:
- Oil Pressure Warning Light: Most modern vehicles have an oil pressure warning light on the dashboard. If this light illuminates when the engine is idle, it’s a clear indication of low oil pressure.
- Loud Engine Noises: A lack of sufficient oil pressure can cause increased friction between engine components, leading to loud knocking or tapping noises, often referred to as “engine knocking.”
- Poor Engine Performance: Low oil pressure can result in reduced engine performance, including decreased power and responsiveness.
- Engine Overheating: Inadequate lubrication can lead to increased engine temperatures. If your engine temperature gauge shows elevated readings, low oil pressure could be the cause.
What Causes low oil pressure at idle?
Oil pressure should always stay within the manufacturer’s predefined range. This means it should never go too low or too high. Older cars have an oil gauge indicator on the instrument cluster that shows the oil pressure range. It usually reads between 50 to 70 psi.
On the other hand, newer vehicles do not have an oil pressure gauge. Instead, they are built with an oil warning light that comes on whenever the oil pressure goes below 50 to 70 psi, depending on the car model.
Always pay attention to the oil pressure. If you have older cars with an oil pressure gauge on the dashboard, ensure the pressure needle does not go down to the danger zone. And if you have newer model cars, ensure the warning light is not displayed on the dashboard.
If the pressure gauge goes to the danger zone or the warning light pops up, pull over and see what could be the culprit. Ensure you do not continue driving the vehicle until you track and resolve the leading cause. What causes low oil pressure at idle anyway?
Low oil pressure at idle means the oil pressure is low when the engine is running at idle. The leading causes could be a defective oil pump, low oil level, bad oil quality, a lousy oil pressure gauge, or you’re running with the wrong oil type for the current weather or vehicle.
#1. Poor oil quality.
This commonly results from not changing the engine oil when you’re supposed to. If motor oil becomes dirty or contaminated, the quality starts to depreciate. It’ll start losing its cooling and lubricating properties.
The oil compounds change, and the cleaning additives used in the formation process dissipate. As a result, the engine will start building sludge.
#2. Low motor oil level.
If the oil drops below the recommended level, the oil pump may be unable to circulate the oil to every part of the engine, especially around the top cylinder. As a result, the related sensors will signal to the car computer.
The powertrain control module will then project the oil warning light, or the oil pressure gauge will start dropping to the danger zone to notify you of an underlying problem. The warning light will likely come up when driving through a corner or curve.
A low oil level can simply be an oversight or caused by a leak around the system. It could also mean the engine is burning oil. Low oil levels can also cause low oil pressure when warm.
#3. Clogged or low-quality oil filter.
Believe it or not, it’s better to use a high-end oil filter than high-end engine oil. I’m not saying you should use low-quality oil for any reason, rather my point is that you should not buy low-quality oil filters.
A low-quality oil filter can easily clog and prevent adequate oil flow to the internal engine parts.
The Premium oil filter also clogs if you fail to change them at the oil service interval. Changing the oil and the oil filter is recommended for optimum engine performance. A clogged oil filter can also cause low oil pressure when hot.
#4. Wrong oil grade.
Like the oil filter, changing the engine oil with the wrong oil grade may lead to low oil pressure after the oil change. Undoubtedly, some engines can run on various oil grades, but some require a specified oil grade for optimal performance.
Depending on your engine, if the oil is too thick, it may not flow properly. While one engine may require a thin oil, another will require a thick oil for proper lubrication and cooling.
#5. Faulty oil pressure gauge.
A faulty oil pressure gauge may be responsible for low oil pressure at low RPM. This mostly happens after an oil change until the system resets and registers the new oil viscosity.
If this starts after an oil change and continues for an extended period, you need to examine the oil pressure gauge. It could be you have electrical issues. This can also result from a wrong oil grade, low oil level, or poor quality oil filter.
#6. Lousy oil pump.
The oil pump is an essential engine part that helps circulate the engine oil to every internal part in need of oil. If this component fails, it’ll stop circulating the motor oil. Once this occurs, the oil warning light will start flashing or stays lit on the dashboard.
You will hear strange clicking, tapping, or rattling noises inside the engine cylinder. Do not drive the vehicle with this sign, even for the shortest trip.
Driving with a failed oil pump can lead to a catastrophic engine breakdown, requiring an overhaul or entire engine replacement.
#7. Engine damage.
In a worst-case scenario, it could be the car engine is damaged. Certainly, you don’t want this to happen. Yes, you can avoid this if you cultivate a regular maintenance culture.
If none of these probable causes are the leading cause, you need to check for other symptoms the engine is projecting for easier diagnosis.
Also, scan the vehicle and pull out all the registered fault codes to check the meaning. From there, it may be easier to track and fix the root cause.
How do you fix low oil pressure at idle?
If you want to repair the low oil pressure situation, it’s best to tackle the problem the same way professional technicians do. Here’s what we would do, and you can try it as well.
#1. Check the Oil Level.
Your first step is to check how much oil is in the system. You can do this by pulling out the oil dipstick and reading the level. It should be between the empty and full marks on the stick. If it’s not, you need to add more oil.
If the engine continues to drop low in oil, you may be dealing with an oil leak. You should inspect the system to see where the oil is dripping from. There can be a leak in the oil pan or one of the seals. It could also be coming from a gasket.
#2. Oil and Filter Change.
If the oil level is okay, but you notice that it’s dirty or contaminated, it’s time to perform an oil change. You also want to do this if you’ve accidentally used the wrong oil viscosity.
Most manufacturers recommend an oil and filter change every 5,000 to 10,000 miles, depending on what type of oil you use. However, if you are hard on your vehicle, you may need to get more frequent changes.
Towing heavy loads or operating your car in mountainous terrain all take a toll on the engine and the oil. Changing the oil more frequently only helps it remain in better condition to protect the motor.
#3. Test Oil Pressure With a Manual Pressure Gauge.
If you think there might be something wrong with the gauge, you can test the oil pressure manually. Here are some basic steps to follow.
- Lift the front end of the vehicle to provide more clearance.
- Find the engine oil pressure sender. It’s sometimes located near the oil filter housing.
- Place a drain pan under the engine to catch any spillage.
- Take off the electrical connector from the sender.
- Remove the sender from the block with a socket.
- Attach the oil pressure gauge.
- Check the oil level and top it off if needed.
- Run the engine at idle for five minutes, allowing it to reach normal operating temperatures.
- Reference the service manual to determine the appropriate RPM to run the oil pressure test at.
- You also want to know the proper oil pressure range for that RPM based on information from the service manual.
- Record the oil pressure readings.
- Turn off the engine.
- Let the engine cool down.
- Remove the tester and reinstall the sender.
- Reinstall the electrical connector.
- Carefully lower your vehicle back to the ground.
If you are getting a different reading manually than what’s showing on the dash, the gauge or sensor could be faulty.
#4. Inspect the Oil Pump.
If you think the oil pump may be to blame, you need to remove it from the motor for an inspection. Take the cover off of the pump so you can look for signs of wear. There may be heavy scoring inside the cover.
You should also look for metal particles in the pump body. Be mindful of how everything comes apart so you can put it back together when you are done.
If the pump shows wear, you want to replace it with a new one. If it still looks good, you can consider cleaning it up and reinstalling it, but most people just decide to replace it.
The oil pump is often located inside the oil pan and is often difficult to reach. Therefore, you should be absolutely sure that you have checked everything else before starting this process.
#5. Contact A Professional.
It’s not easy to deal with low oil pressure on a car. A lot of the problems could be advanced and above your mechanical understanding. If so, it’s best to reach out to a professional.
Check online reviews before choosing a mechanic. When dealing with the car engine, you don’t want to take any chances by using someone with a lack of understanding.
How To Prevent Low Oil Pressure At Idle?
#1. Oil changes regularly.
Maintaining clean, fresh oil is crucial for preventing low oil pressure at idle. Over time, oil degrades, losing its viscosity and ability to lubricate effectively.
Dirty oil also contains contaminants that can clog oil passages, further restricting oil flow and contributing to low pressure.
Regular oil changes ensure that the engine receives the proper lubrication it needs, maintaining optimal oil pressure at all engine speeds, including idle.
#2. Use the correct oil viscosity.
Oil that is too thin (low viscosity) will not provide adequate lubrication at higher temperatures and may lead to low pressure at idle.
In contrast, oil that is too thick (high viscosity) can create excessive resistance and impact oil flow and pressure, particularly when the engine is cold.
The correct viscosity ensures proper lubrication and maintains the designed oil pressure within the engine.
#3. Replace the oil filter.
The oil filter prevents contaminants from clogging oil passages and reducing oil pressure.
A clogged or dirty oil filter restricts oil flow, which directly impacts oil pressure, particularly at idle when the oil pump is operating at its lowest speed.
You should regularly check and replace the oil filter, with every oil change, ensure unrestricted oil flow and maintain optimal oil pressure.
#4. Beware of oil leaks.
Oil leaks can significantly contribute to low oil pressure, especially at idle. Leaks can occur from various locations, such as the oil pan gasket, valve cover gaskets, or even the oil filter itself.
These leaks reduce the overall oil volume in the engine, leading to lower oil pressure.
#5. Identify underlying engine problems.
Sometimes, low oil pressure at idle indicates a more serious underlying engine problem.
Worn engine bearings, a failing oil pump, or even a malfunctioning oil pressure sensor can all contribute to low oil pressure readings.
Sometimes, it’s crucial to have the engine thoroughly inspected by a qualified mechanic. They can diagnose the root cause of the problem and recommend the necessary repairs.
FAQs.
Q: Why is my oil pressure low but oil level OK?
Low oil pressure doesn’t necessarily mean you have a low oil level. If the oil warning light blinks or stays lit on the dashboard, it could mean you have contaminated or dirty engine oil, failed oil pump, wrong engine oil, or a clogged or low-quality oil filter. Check these probable causes when diagnosing the leading cause of low oil pressure.
Q: What is a safe oil pressure at idle?
Safe oil pressure on idle is 20 to 30 psi. Something is wrong if the oil pressure runs below this psi when sitting.
But on high rev, the oil pressure gauge should stay between 50 to 70 psi. If the pressure drops below this level, inspect the oil level, conditions, and other probable causes.
Q: Is 20 psi oil pressure good?
Any pressure below 20 psi on idle is considered low. On the other hand, anything below 50 psi on high rev is considered low.
This is commonly caused by insufficient oil levels, dirty or contaminated oil, and defective oil pumps. However, other issues, such as the ones highlighted above, can also be the leading cause.
Q: Will adding oil fix low oil pressure?
As simple as adding engine oil, it will fix a low oil pressure if the culprit is low engine oil. However, factors like engine burning oil, worn piston rings, oil leaks, excessive blowy, and worn valve seals or guides can also cause low oil levels.
If any of these is the root cause of the low oil level, adding engine oil will temporarily fix the low pressure. But you’ll need to fix the actual cause to maintain a permanent fix.
Q: Is it OK to drive with low oil pressure?
Low oil level is a serious issue you won’t want to joke with. If you continue driving with a low engine oil level, the engine will incur catastrophic damages that may lead to overhauling or engine replacement.
Contact a service technician to track and resolve the leading cause once you have low oil pressure.
Q: Will thicker oil increase oil pressure?
Some experts believe that thicker oil will increase oil pressure, such as increasing from 5w-20 to 10w-30; I advise you to take this with a grain of salt. Well, this slight change may increase the bearing clearance, enhancing the oil pressure.
Q: Can a clogged oil filter cause low pressure?
A clogged or dirty oil filter is one of the common causes of low oil pressure. If you just replace the oil filter, chances are you bought an inferior filter, which is as bad as a dirty filter.
Oil filters have oil relief valves. If these valves fail, the motor oil will pass right through, reducing the oil pressure.
Q: How much does it cost to fix low oil pressure?
It is nearly impossible to accurately estimate the repair cost of low oil pressure. This is because several factors are to be considered.
However, the cost of fixing low oil pressure can be as little as $20 or as high as $2,000, depending on your car’s make and the root cause.
For example, if the solution is to add extra oil to the engine, it won’t cost more than $20 to fix it.
But if the root cause is a failed oil pump, then you should budget to spend between $350 and $2,000. You may even pay more if the problem has damaged internal engine components.
Final Words
Several factors can cause low oil pressure at idle. Once this happens, the oil warning light will illuminate the dashboard.
With or without the oil warning light or the oil pressure gauge reading, do the needful by performing regularly scheduled oil changes and other car maintenance.