Causes of Oil Pressure Drops When Engine Heats Up

You might have noticed that your oil pressure drops anytime you’re driving, and you might wonder what the problem is. Whenever you experience that your oil gauge drops to zerowhen driving or idling, something is not right.

In this article, we will look at the causes of oil pressure drops when engine heats up. We will also answer questions like how do you fix an oil pressure drop? Is it OK to drive with low oil pressure? And other related questions.

oil pressure drops when hot

Why Oil Pressure Drops When Engine Heats Up

There are a lot of factors that could cause low oil pressure when the engine heats up. It could be due to normal occurrences or could be tied to issues related to the engine. All these depend on how much oil pressure drops when hot.

Before we can go on, we must understand what oil pressure is. Oil pressure is the pressure between the oil pump and the bearing. When oil is too low, it indicates a problem with the oil pump or bearings. If the oil pressure is too high, it shows that the oil cannot flow properly. 

Oil pressure could drop when the engine gets hot for two major reasons. The first one is the change in the oil viscosity as it becomes thinner due to the heat. The second is an expansion of engine parts due to the heat generated by the engine. The damaged oil pump or pressure relief valve are also liable.

When the engine gets hot, the engine bearing expands and gets bigger. It creates a bigger space for the oil to move, thereby reducing the oil pressure in the engine. Now the oil can slip through much easier.

Also, the temperature of the engine has a direct effect on the viscosity of the engine oil. As the engine gets hotter, the viscosity of the oil drops or engine oil expands. When this happens, the oil gets thinner and can slip through the engine.

Oil pressure drops when the oil is much thinner, and the pump cannot pump it as effectively as when it is thicker.

Other factors could cause low oil pressure when hot, including the following.

1. Using the wrong oil viscosity

2. Low oil level

3. Using old oil

4. Worn-out bearings

5. Defective oil pump

6. Dirty oil filter

7. Faulty Pressure Relief Valve

How Do You Fix An Oil Pressure Drop?

To better fix an oil drop pressure, you must understand what would cause oil pressure to drop. Below we will look at some common reasons why oil pressure keeps droppingwhen the engine gets hot and how to fix them.

1. Wrong viscosity oil using

It is best to use the specified oil viscosity for your vehicle. Using engine oil that is too thin will drop the oil pressure when it is heated up. When this happens, you will have a situation when the oil pressure gauge drops to zero. Thus, mixing different viscosity oils are not recommended.


You might need to drain the oil if you use a thinner oil. Once you can drain the oil, change the oil filter also. Check the manual of your vehicle for the specified oil viscosity for your vehicle. Refill with new oil with the specified oil viscosity for your vehicle.

2. Low engine oil level

The most common cause of low oil pressure is the low oil level in the engine. Leaks or other engine problems could cause this problem.


The first thing to do in this situation is to check the oil level using a dipstick. If the oil is full, the low oil level is not the cause of the low pressure. However, if the oil is low, you may need to top off your oil. 

3. Using contaminated oil

When you do not change your vehicle’s oil at the recommended oil change interval, you might face an oil pressure problem. Old or contaminated oil will lose its viscosity, affecting oil pressure.


The best fix for this is an oil change. You must drain all the old oil and refill it with a new one.

4. Worn-out or missing bearings

With time parts of the engine become worn out, and when it comes to low oil pressure, the bearing is a major target. A worn-out or missing bearing will not allow accurate oil pressure. It instantly causes oil pressure drops till it hits Zero.


Inspect the engine bearing and locate which is worn out or missing. Once you can locate it, replace the bearing with a new one.

5. Damaged oil pump

The oil pump is responsible for distributing oil to various engine components. When the oil pump is damaged, an oil pressure drop is a major sign you will get from your vehicle. The oil gauge drops to zero, and you start having engine problems due to the lack of oil flow.


The best fix for this is to replace the faulty oil pump. Before doing this, you must ensure the oil pump is damaged.

Is It Ok To Drive With Low Oil Pressure?

Driving with low oil pressure is not okay, as it could cause severe damage to your engine. A low oil pressure shows that there is something damaged in the engine and there is not enough oil flowing through the engine.

When you drive with low oil pressure, you drive a vehicle starved of oil. There will be increased friction within the engine parts which could lead to overheating, wearing of engine parts, and eventually, engine failure.

It is best to fix whatever could cause the low oil pressure rather than risk a potential engine failure that could cost even more.

Will Adding Oil Fix Low Oil Pressure?

The fix for a low oil pressure depends on the cause of the problem. If the cause of the oil pressure issue could be traced to low oil, then adding oil will solve the problem. If you have an old or contaminated oil, you might have to get the oil changed immediately.


When you notice that your oil pressure drops, the first step you should take are finding out what could have caused it. Once you can diagnose the cause of the problem, it will be easier to fix it. It is best to have professional help with the diagnosis and fix it for a perfect job.

Akindayini Temiloluwa

I am Akindayini Temiloluwa, an automotive expert writer and car enthusiast. I have over three years of experience in the automotive writing niche and have completed over 300 pieces of content from 50 projects. I have vast knowledge and skill in vehicle repairing, all mechanical work, car upgrades and maintenance. My goal as an automotive content writer is to simplify the most challenging concepts for my readers, help them self-diagnose what may be wrong with their vehicles and offer real value for their time.

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