Oil Pressure Dropping When Hot: 8 Reasons With Solutions

Is your oil pressure dropping when hot? There could be a lot of reasons why this is happening, but in any case, it is a serious problem that you should immediately take care of

Oil pressure is the most important parameter in running the engine smoothly. It is very similar to blood pressure in the human body – the same way blood pressure ensures that blood and nutrition are reaching every part, oil pressure ensures that oil reaches all parts of the engine. Low oil pressure is just as bad as low blood pressure for the engine.

Whenever the oil pressure light is illuminated on the dashboard, you should make sure that you attend to it immediately. One problem that often occurs is that you find the oil pressure to drop significantly whenever the engine gets hot. There are many reasons for this.

For instance, if there is low oil inside the reservoir, you may face such an issue. Similarly, dirty oil filters, damaged bearings, using low viscosity oil, and improper functioning of the oil pump can be the reasons for which the oil pressure gets reduced drastically.

Oil Pressure Dropping When Hot

Why Does Oil Pressure Drop When Hot?

A lubrication system is quite essential for a vehicle. There must be a sufficient amount of oil inside the reservoir, and it should flow under proper pressure so it can lubricate various engine components, like a piston, crankshaft bearings, and many more.

The oil pressure varies from one vehicle to another. But the ideal oil pressure is within 25 to 65 psi after getting hot. But if the oil pressure drops below 25 psi after getting hot, it will be unable to reach various engine components and massages, resulting in engine overheating. The engine may even seize to operate. There can be various reasons the oil pressure can reduce when hot. We are listing some of them below.

#1. Low Oil

The lubrication system mainly comprises of oil pump, filter, pressure relief valve, oil strainer, and sump. The oil starts to flow and lubricate various engine components whenever the engine begins to run.

The oil pump is the primary component of the engine lubrication system. It is connected to the engine crankshaft by bet and pulley arrangement and thus receives power. Once the oil pump receives power, a suction is instantly produced in the oil strainer, and therefore, it starts extracting oil from the oil sump.

The oil pump draws oil from the strainer and then sends it to the secondary filter. A pressure relief valve between the oil pump and the secondary filter helps regulate the correct pressure to flow in the galleries and oil lines.

But low oil inside the reservoir is the most common reason the oil pressure can be reduced when hot. Most car owners don’t change the oil for a long time. It can be a reason for low oil inside the reservoir.

Additionally, leaking oil can be the reason for which there can be low oil inside the reservoir. The oil can leak from various places, including oil filters, gaskets, and many more.


Oil Pressure Dropping When Hot

Another thing you need to keep in mind is that when the engine becomes old, it starts to use more oil. So always check the oil reservoir within a gap of a few days. Low oil can create issues in the engine.


Using the dipstick, you need to check the oil level inside the reservoir. If you find a sufficient amount of oil inside the reservoir, then low oil is not a problem. But if there is low oil inside the reservoir, pour oil and check the oil pressure.

If the problem still lingers, then there can be other reasons for which oil pressure drops upon getting heated.

Also read – Good idea to have a magnet in the oil pan (collects magnetic waste)?

#2. Using Oil Of Incorrect Viscosity

The viscosity of oil dramatically affects the oil pressure. Imagine dropping oil on an inclined surface. It will flow down because of gravity. But if the oil has a high viscosity, it will take longer to reach down.

So you can define viscosity as fluid resistance. So, if you use low-viscosity oil, it will have less resistance; thus, the oil pressure is reduced when it is hot. It fails to lubricate all the engine components properly.

The oil’s viscosity is also affected by oil temperature, i.e., it decreases with the increase in oil temperature and vice versa. So if you use low-viscosity fluid, it will become thinner on becoming hot. Consequently, the oil pressure gets reduced.


You need to use the proper viscosity oil to lubricate all the engine components. So, if you use low-viscosity oil, check the owner’s manual and use the proper viscosity oil to solve the problem.

#3. Irregular Oil Change

The oil’s viscosity reduces if you don’t drive your car long. It becomes too thin that it affects the pressure. The oil pressure can get reduced drastically when hot because of this reason.


If you have not changed the oil for a long time and are facing a low-pressure issue, try to drain out all the old oil. Top the oil reservoir with new oil. Ensure to use oil of the proper viscosity. If possible, change the oil filter if it has become too dirty.

Oil Pressure Dropping When Hot

#4. Damaged Or Missing Bearings

Multiple engine components can get damaged with time. But the most common component is bearings. If the bearings are missing or worn out, it can reduce the resistance of oil flowing in the galleries and oil lines, and consequently, it severely affects the oil pressure, i.e., it will become low upon being heated.


You need to invest in the bearings and find out which is worn out. You must replace the damaged bearings with a new ones. Do it as soon as possible because neglecting it can have an adverse effect on the engine.

#5. Oil Pressure Gauge Malfunction

You may panic when the oil pressure light illuminates the dashboard. But what if you checked the oil reservoir and found the proper oil inside it? Moreover, you observe that the engine also runs perfectly with no unusual sound – what could that mean?

If this is the case, the oil pressure gauge can have some issues, for which it is showing the wrong reading. The main work of the oil pressure gauge is to read the oil pressure flowing in galleries and oil lines. But it can malfunction with time.


Changing the oil pressure gauge on your car is the best way to solve the problem. But if the problem persists even after changing the pressure gauge, there may be some issues with the oil pump.

#6. Damaged Oil Pump

The oil pump plays a significant role in disturbing oil to various engine components. The pump draws oil from the strainer and sends it to the secondary filter.

The filter removes all the dust and debris so that clean oil can flow in the galleries and pipelines and finally reach the crankshaft, piston, and other engine components. The oil lubricates and helps in keeping the engine parts cool. But when the oil filter becomes bad and doesn’t function properly, there is a severe reduction of oil pressure, especially when it is warm.

There are several reasons for oil pump failure. For instance, if you have not installed the oil pump properly, it can damage within a short time.

Additionally, the pump must do extra work if the oil level is low in the reservoir. It will increase the friction between its various parts. It can be the reason for the failure of the oil pump. Again dust, dirt, debris, or other contaminants in oil can be responsible for the malfunctioning of the oil pump. When the oil pump goes bad, you will hear a whining or grinding noise, mainly when the engine is idle.


If you inspect the oil pump and find it poorly damaged, replace it with a new one. Try to do it as soon as possible because a faulty oil pump can increase the engine’s operating temperature. Additionally, it will increase the friction between all the moving parts of the engine, which can finally lead to an engine stall.

#7. Dirty Oil Filter

The work of an oil filter is to remove all the dust and dirt from the oil before entering the engine components. But the oil filter gets dirty on continuous removal of dust and dirt. The filter can also get blocked because of water and soot particles.

Oil cannot flow under normal pressure in oil lines whenever the oil filter gets dirty. Oil pressure is usually reduced when heated, which becomes a severe problem for the engine.


Replace the oil filter if it has become too dirty. We recommend you change the oil filter every time you change the oil to avoid the low-pressure issue.

Oil Pressure Dropping When Hot

#8. Malfunctioning Of Oil Pressure Sending Unit

The oil pressure sender unit measures the oil pressure and sends the information to the Electronic control unit, showcasing the reading. But if the sending unit is not working correctly, it will end with false information to the ECU and consequently show incorrect readings.


If the oil pressure sender unit is faulty or not working effectively, replace it with a new one. It’s better to do this by taking the assistance of any professional mechanic.

What Are The Signs Of Low Oil Pressure?

#1. Oil Pressure Light Is Illuminated

When the oil pressure is low then you will observe the oil pressure light will be immediately illuminated on the vehicle dashboard.

The oil pressure sensor monitors the oil pressure in the galleries and oil lines. When the pressure fluctuates from the normal pressure range, it lets you know by illuminating the dashboard. But if the oil pressure sensor malfunctions, it will show the wrong information.

#2. Noise From Engine

If the oil pressure becomes low, you will hear a rattling noise from the engine. The engine components can rub against each other because of inadequate lubrication. Try to switch off your car engine immediately after hearing the rattling or rubbing sound.

#3. Check Engine Light

If the oil pressure reduces to the normal range, the check engine light starts illuminating the dashboard.

#4. The car Engine Ceases

Your engine can seize when the oil pressure reduces drastically. You have to spend thousands of dollars on repairing your car.

Tips To Remember For Maintaining Proper Oil Pressure

Oil pressure is extremely important for your car. Here are a few things that you should always do in order to keep your oil pressure healthy.

  • Always use the proper viscosity oil in your car, i.e., according to the manufacturer’s recommendation.
  • You must check the oil within a gap of two to three days. If you find low oil inside the reservoir, top it with more oil.
  • You must replace the oil filter while flushing the old oil and replacing it with a new one.

Frequently Asked Questions

#1. Why does my oil pressure drop when it gets hot

The viscosity of oil usually drops when it passes through the engine passages as they are at higher temperatures. There is a reduction in pressure because of low viscosity.

So, you must use the proper oil viscosity, i.e., as per the manufacturer’s recommendation. There are other reasons too for which the oil pressure can drop. For instance, if the bearings are worn out or bad filter and malfunctioning of the oil pump is.

So, detect the reason for which the oil pressure has dropped drastically in your car and correct it accordingly.

#2. What causes low oil pressure at a hot idle

There are various possible reasons why the oil pressure can drop when the engine is in idle condition. We are listing some of them below.

  • Low oil inside the reservoir.
  • Using incorrect oil
  • Malfunctioning of the oil pump
  • Bad oil quality

Oil Pressure Dropping When Hot

#3. How do you fix an oil pressure drop?

You can fix the oil pressure drop by following the ways

  • Use high-viscosity oil or as recommended by manufacturer instructions
  • Replace the damaged bearings
  • Replace the oil filter if it is too dirty
  • Replace the oil pump if necessary

#4. Why does my oil pressure randomly drop?

There could be many reasons why the oil pressure is dropping randomly. Perhaps there is a leak in the engine, which is causing oil to slowly seep out.

You might be using engine oil of different brands, one of low viscosity and the other of a high one. Lastly, it is possible that the oil gauge is damaged and is showing the right pressure only sometimes but not others.

Wrap Up

The oil pressure should maintain appropriately for the smooth running of the engine. But if it becomes low when hot, it can affect the engine components badly.

We have discussed above the reasons behind the oil pressure becoming low and what you can do to prevent it. We hope it will be helpful to you. Thank you for reading this article!

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Sean Mendez

Hi, I am Sean, a self-confessed petrolhead. I live in Boise, Idaho with a busy family of four and our energetic Labrador retriever. Thank you for visiting my website. You can find my email on the contact page.

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