What Causes Low Oil Pressure at Idle? – 7 Main Reasons

Written by

Charles Bolte


Vernon Hoppe 

what causes low oil pressure at idle

What causes low oil pressure at idle? The reason can be as simple as low oil levels, which you can resolve by topping up with engine oil.

However, the cause can be as serious as oil pump problems or engine damage. If so, you might need assistance from a professional or mechanic.

Whichever the reason, you should resolve it immediately. Otherwise, you’ll leave your engine unlubricated, making it more prone to wear and tear.

Why is Oil Pressure Low at Idle?

Typically, the oil pressure drops at idle. That is, from 25 PSI to 65 PSI (for a typical car), it goes down to 20 to 30 PSI.

However, when the oil gauge goes down to below 20 PSI, you should be concerned as the underlying reasons may be severe, such as:

1. Low Oil Level


Over time, oil burns up or becomes too thin. Thus, if you haven’t topped up or changed your engine oil in a while, then your engine may be lacking oil, and that causes the low oil pressure.

However, if you’ve added engine oil recently and lost a significant amount already, there might be a leak in the seals or oil line.

If so, you must determine where that leak is and seal it. Otherwise, you’ll constantly lose engine oil, leading to further damage.

It’s also essential to note that old engines consume more oil than new ones. Thus, if your car is old, you may have to change or top up with oil more often.

2. Poor Choice of Engine Oil


If your engine has adequate engine oil, the problem could be with the type or brand of oil you use.

When you buy engine oil, you may notice different types and grades. You must purchase the one that matches your vehicle, or your engine won’t achieve optimal performance.

For instance, if you buy oil of the wrong grade, its viscosity may not match your vehicle. Specifically, if it’s too low, the oil won’t be able to reach a good oil pressure level for your car.

Meanwhile, if it’s too high, the oil pump cannot deliver the oil to all components that need lubrication. This scenario will also lead to low oil pressure levels for your vehicle.

If you bought the correct grade, then the mismatch might be with the brand. Some brands opt for the lower viscosity end of the grade, so adding it to your engine may lead to low oil pressure.

Consult your manual to know the best engine oil for your car. It may even specify a brand, blend, and grade for high-end vehicles.

3. Faulty Oil Pressure Sensor/Gauge


Sometimes, there’s no actual issue with the oil pressure level. Instead, the oil pressure sensor is faulty. But what is this sensor?

Firstly, you should know if your vehicle has a gauge or indicator light to inform you if the car’s oil pressure level is no longer normal.

If you have a gauge, you’ll monitor it to see if the arrow or line is beyond the normal range. Meanwhile, those with an indicator light will know something is wrong when the light blinks or is lit up.

Either way, those two devices rely on the oil pressure sensor to provide proper signals. Thus, if the sensor is faulty, it might indicate that the engine has low oil pressure at idle, even if it is not.

4. Oil Filter Issues


The oil filter is essential for removing debris and contaminants in the engine oil. The more and longer it filters, though, the more likely it gets clogged.

Your sensor will detect low oil pressure when the oil can’t flow because of a clogged filter. Thus, you must change your oil filter regularly to avoid such problems.

5. Oil Pump Problems


Engine oil is pumped through the engine to reach all components and keep them well-lubricated. If there’s a problem with the oil pump, the engine oil – even with the correct blend or grade – can’t reach those components.

Thus, check if your oil pump is damaged or not. If it is, have it fixed or replaced immediately.

6. Worn Bearing Clearances


When it’s warm, the oil thins out. Thus, you can expect the oil pressure to drop slightly when your engine is warm or heated.

However, if the oil pressure difference between your hot and cold engines is too much, your bearing clearances may be worn out.

7. Engine Damage

As much as possible, you don’t want engine damage to be the underlying reason for your low oil pressure. That’s because the oil pressure is the least of your worries when that’s the scenario.

Engine damage can render your car incapacitated. Depending on the severity, you must fix or completely replace it. Either way, it can be costly and a hassle.

Thus, maintain your car and its engine well. Pay attention to issues such as clogged oil filters or low oil levels, as they could lead to engine damage, which is harder to address.

Signs of Low Oil Pressure at Idle


To resolve low oil pressure, you must know its symptoms:

  • Oil gauge arrow is below normal: If you have a gauge on your dashboard, observe the arrow to see if the oil pressure level has fallen below the normal or minimum level.
  • Oil pressure indicator light is on: Modern vehicles usually don’t have dashboard gauges. Instead, there’s a light that turns on or blinks when there’s a problem. Be sure to know where that light is and keep an eye out for it.
  • Poor engine performance: If there isn’t enough engine oil or it isn’t circulated well, the engine can’t function properly. You may also hear clunking sounds when the engine isn’t working well.
  • Overheated engine: Engine oil prevents too much friction in the engine. Thus, when there’s low oil pressure, friction increases, leading to excess heat in the engine.
  • Oil drips: If a leak in the line causes the oil pressure, you’ll notice some oil drips under or around your car.

How to Fix Low Oil Pressure at Idle


You can follow this flowchart when your vehicle has low oil pressure:

Besides the flowchart, here are some tips you can try to fix low oil pressure at idle:

  • Top up with engine oil: If your engine is low on oil, you must fill or change it with the proper blend and grade.
  • Change engine oil: If you think the current engine oil in your vehicle isn’t a good match, change it with the one recommended in your manual.
  • Change the oil filter: If there’s no oil problem, check your filter to see if it’s clogged with debris or deposits. If so, replace it immediately.
  • Test the oil pressure sensor: A multimeter is often used to check if the oil pressure sensor is working perfectly well.
  • Manually check oil pressure: You can manually check the oil pressure level using an oil pressure tester.
  • Inspect oil pump and engine: You should assess if the pump and engine have apparent problems, then evaluate if you can resolve them independently. If you can’t determine obvious issues, consult a professional.

What is Normal Oil Pressure at Idle?

What should your oil pressure be? According to several sources, it should be 25 to 65 PSI for cars and 30 to 70 PSI for trucks. However, that’s only when the vehicle is up and running.

When you stop, and the vehicle is idle, the pressure will drop slightly to 20 to 30 PSI for cars and 25 to 35 PSI for trucks. But if you have your manual, check it for the correct values for your vehicle, as there might be slight differences.

If the value goes any lower than your vehicle’s minimum oil pressure at idle, you likely have an issue with the oil, filter, pump, sensor, or engine.

Tips to Check Oil Pressure


Remember these tips when you manually check your vehicle’s oil pressure with an oil pressure tester:

  1. Prepare your tools and equipment beforehand, which includes an oil pressure tester, rags, drain pan, wrench, or pliers.
  2. Get an oil pressure tester that matches the thread of your vehicle’s oil pressure sender.
  3. Check your vehicle’s manual to know the accurate normal oil pressure range and whether you should conduct your oil pressure test at low rpm.
  4. The engine should be cold when you remove the oil pressure sender. When it’s hot, the oil will spray instead of trickling, creating a mess.
  5. Test your vehicle’s oil pressure levels at idle, cold, and hot conditions, and compare. If there are apparent differences, assess for possible underlying issues.

Risks of Low Oil Pressure

Oil protects your engine’s components from rapid wear and tear. Low oil pressure puts those components at risk of damage because it means that there’s little to no fluid protecting them from abrasive friction.

Furthermore, if such conditions persist, you’re facing potential engine damage. Thus, you should prevent and address them immediately.

How to Prevent Low Oil Pressure


Proper and regular maintenance is critical to preventing low oil pressure. Thus, you should habitually change your oil and oil filters at the right time.

Maintenance also includes technician checkups. These consultations allow you to identify issues and address them immediately if there are any.

If you do all those, your low oil pressure situations in the future are less likely to be caused by grave problems like engine damage.

How Do I Increase the Oil Pressure at Idle

You can usually increase oil pressure at idle by adding or changing oil. The usual underlying issues are a lack of oil or the one in your engine was not replaced on time, so topping up or changing is a quick and appropriate fix.

However, if the oil pressure is still low but the oil is full, stop the engine. Then, check your engine, pump, filter, bearings, and oil sensor for issues.

If you could identify the cause of low oil pressure, resolve it if possible. Otherwise, it’s best to seek help from a mechanic or technician.

Frequently Asked Questions


What Is the Importance of Oil Pressure?

Oil pressure is important because it indicates if oil is appropriately circulated throughout the engine system. When that’s stopped, the engine components are left unprotected from fiction, leading to wear, tear, and overheating.

Can Driving With Low Oil Pressure Cause Permanent Damage?

Driving with low oil pressure can cause permanent damage because the engine’s metal parts are left to rub against each other with little to no oil, which would’ve prevented too much friction. This friction can be abrasive and damaging, causing wear, tear, and overheating of components.


What causes low oil pressure at idle? To sum up, oil pressure is reduced by pump problems, engine issues, or worn clearance bearings. Forgetting to change and top up your engine oil could be another possible cause.

When those underlying issues are left unaddressed, you’ll not only be dealing with frequent low oil pressure warnings. You might even face permanent engine damage in the future, which can be expensive and time-consuming to manage.

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