The oil pressure light is a critical indicator of the engine condition. It tells you that something is wrong with the oil pressure, and you should take a look at the problem.
So, why does the oil pressure light come on when the engine is hot? A hot engine can make the oil thinner and cause the pressure to drop. Also, the engine consumes more oil when it is hot, causing the oil pump to push oil at a high pressure. Sometimes, the oil pressure sensor can be faulty and turn the oil pressure light on.
Let’s diagnose each of the reasons behind this problem and try to solve them effectively.
Oil Pressure Light Comes On When Engine Is Hot: Causes and Solutions
A long list of reasons can be responsible for this problem. Here is a detailed overview of them.
1. The Engine Is Consuming More Oil
Engine temperature is closely related to the oil pressure and viscosity. When the engine is cool, the engine oil has a higher viscosity. So, it flows slowly, and the pressure is normal inside the system. When the engine gets hot, the engine oil temperature also increases.
As a result, the viscosity of the engine oil decreases. It starts to flow faster, and the engine consumes more oil. This creates a temporary loss in oil pressure. This pressure loss can trigger the oil pressure sensor. The oil pressure sensor will then turn the oil pressure light on.
- The oil pressure gauge on the dashboard may show a slightly lower pressure than normal.
- The oil light may come on and go off automatically.
- This is a normal condition for most engines. The oil pressure may drop temporarily when the engine is hot.
- When the oil pump delivers more oil, the pressure will be balanced, and the oil pressure light will go off. You don’t need to do anything about this.
2. Engine Oil Level Is Low
This is related to the previous situation. When the engine oil level is normal, the oil pressure light will come on and go off. But if the oil level is low, the pump can’t cope with the increasing oil demand.
As a result, there will be a pressure drop in the system. The oil pressure sensor will detect the low pressure and cause the oil pressure light to come on.
- The oil pressure light will illuminate steadily if the oil level is low.
- Even though the oil pressure gauge drops, the engine temperature gauge will rise due to a low oil level.
- You should turn the car off and let the engine cool a bit.
- When the engine is still warm, take the oil dipstick out. Wipe it off with a rug and then insert it again.
- Remove the dipstick and check the oil level on it. If the oil level is just below the Full line, the problem is with something else.
- But if the oil level is below the Low or Add line, you need to refill the engine oil.
Watch the following video on how to add engine oil to your car.
3. The Engine Oil Has Degraded
When you fill the fresh engine oil, it should have a transparent and bright color. As the oil is used in the engine, it faces extreme temperatures. The oil may break down and produce sludge. Heat also changes the color of the engine oil.
If the oil is too old, it will have a dirty appearance due to the sludge, debris, etc. The viscosity of the oil gets altered due to these elements. So, the oil pressure will be different than normal when the engine is hot. It can cause the oil pressure sensor to turn the oil pressure light on.
- The engine can quickly become hot as the dirty oil might not flow well through the system.
- There can be burning smells from the engine if the oil is exposed to extreme temperatures.
- You should check the oil color and thickness to be sure about the problem. To do this, turn the engine off and let it cool down completely.
- Take the dipstick out and put a few drops of engine oil on a clean surface. Observe the color and thickness of the oil.
- If the oil is too dirty and thick, it indicates the oil has been burnt or contaminated. A frothy texture and creamy color means coolant or water has been mixed with the oil.
- You need to flush the engine oil if it is degraded. Place a drain pan below the drain plug. Then, remove the drain plug and let the engine oil drain completely.
- Pour an engine oil flush liquid into the reservoir. Then, turn the engine on and let the liquid circulate a bit. Remove the drain plug and drain the liquid, too.
- Finally, fill the reservoir with fresh engine oil. Then, turn the engine on and check if the oil pressure light is gone.
4. The Engine Oil Is Leaking
A common reason for the oil pressure light to come on is engine oil leaking. If the pressure gets too high, it can affect the oil seals and gaskets. These components will develop cracks under pressure. The engine oil will start leaking through the cracks.
As a result, the overall oil pressure in the system will drop. This will cause the oil pressure gauge to drop and the oil pressure light to come on.
- There will be visible signs of oil leaks around the engine bay or below the car.
- The engine will start to overheat if too much oil leaks from the system.
- The oil pressure will drop gradually due to the oil leak.
- You should check the oil level first. If the oil level keeps dropping after refilling, there are leaks in the system.
- Finding the engine oil leak yourself can be difficult. I suggest taking the car to a repair shop and getting the system checked for leaks. Fixing leaks may cost about $150-$300, depending on the number and type of leaks.
5. The Engine Oil Grade Isn’t Right
Engine oils have different SAE grades that determine their viscosity level. When the engine is hot, some oils become thinner than other oils. If you use such engine oils in your car, the engine oil can cause a drastic pressure change.
It especially happens when the engine is hot. So, the oil pressure light will come up.
- Besides the oil pressure light, the engine temperature light can come on.
- You may also hear grinding noise from the engine due to insufficient lubrication.
- You should check the recommended engine oil grade in the vehicle’s manual. If you have used the wrong oil, drain the oil by following the steps above and then refill the right grade of oil.
6. Oil Filters or Passages Are Dirty or Clogged
Oil filters usually run for about the same length as engine oils. In most cases, it can be 3,000 to 5,000 miles. During regular use, oil filters catch a lot of dirt and debris. This makes the oil filters dirty.
Over time, they can become clogged and restrict the oil flow. A hot engine requires more oil flow, and a dirty or clogged filter can’t pass the oil that fast. It will increase the oil pressure and cause the oil pressure light to turn on. Excessive deposits inside the oil passageway can also cause the same problem.
- The engine will overheat quickly as the oil flow is restricted.
- There will be metal debris in the oil as a result of friction between engine components.
- You should check the oil filter for dirt or debris. If the filter is too dirty, it is better to replace it.
- Take the car to a repair shop to get the oil passageway cleaned.
The following answers to frequently asked questions might come in handy.
The oil light may flicker at low RPM if the engine oil grade or quality isn’t right. A fluctuation in oil pressure causes this.
You may drive the car for a few miles. But I suggest stopping right away and checking the issue.
Of course. In many cases, the faulty oil pressure sensor shows a wrong pressure reading and triggers the oil pressure light.
So, why does the oil pressure light come on when the engine is hot? A hot engine reduces the viscosity of engine oil and causes the pressure to drop. Besides, low oil levels, degraded oil, clogged filters, or oil leaks can also cause the problem. Use the solutions mentioned here to get rid of the issue.
If any of the reasons you diagnosed don’t come in handy, I would suggest consulting a professional mechanic. Don’t be late, or don’t ignore the issue. This may bring severe consequences.