Ever happened that you started the engine of your car, while your car was idle and you noticed that the oil pressure meter was not reading as high as it was meant to be? If so, you may be facing a common problem that many car owners come across “Low oil pressure at idle”.
In this article, I will help you understand the difference between normal and low oil pressure. We will discuss the causes and symptoms of low oil pressure at idle and how to fix them.
What is Oil Pressure in a Vehicle?
Oil pressure is the force exerted by the engine oil when it flows through the engine. It helps to measure the amount of oil that the oil pump delivers to different parts of the engine.
Engine oil works as a lubricant for the engine. An internal combustion engine will blast without engine oil. Because the engine of a vehicle has numerous moving parts. These parts operate at high speeds and temperatures. If the engine doesn’t get enough lubrication, these parts will experience excessive friction and heat. This will lead to premature wear, damage, and potential engine failure. Here’s where oil pressure steps in as the engine’s protector.
How Does Oil Pressure Work in an Engine?
When the engine is running the oil pump circulates the engine oil throughout the system. This includes passages, bearings, and other crucial components. The pressurized oil forms a thin film between the moving parts and creates a lubricating barrier that minimizes friction and heat generation.
If the oil pressure is low the engine will not run smoothly. Ideally, your car’s engine is built to automatically regulate the oil pressure according to its needs. For instance, when you push the accelerator the components of the engine move faster and generate more heat. To cover this up the oil pumps also begin to spin faster to provide enough lubrication. Similarly, when the engine is idle the oil pressure goes down.
But where do things go wrong? The answer is that, as the vehicle gets old its parts encounter wear and tear. The channels and passages in the engine become void and the resistance to the flow of oil decreases. This simply means that the oil pressure drops compared to normal. Other than the wear and tear there can be several reasons that tend to reduce the oil pressure.
I will explain all the reasons further in this article. Stay connected!
How Oil Pressure is Measured?
The thickness of the oil and the resistance to the flow of oil through the passages and channels determine the oil pressure. Oil pressure is measured in PSI (pounds per square inch).
Most modern cars have an oil pressure gauge on their dashboard which tells the oil pressure of the vehicle in real time.
Engine oil is present in the oil sump which is located at the lower part of the crankcase. When the engine is started the crankshaft and other components start rotational movements, which activates the oil pump. The oil pump then draws the oil from the oil sump and pushes it toward the oil filter.
The filtered oil then passes through several channels and passages and encounters resistance. This resistance generates the oil pressure. The oil pressure gauge is connected to a sensor called the Oil pressure sending unit. It is located near the oil filter. This sensor measures the oil pressure and displays it on the oil pressure gauge on the dashboard.
What is Normal Oil Pressure at Idle?
Normal oil pressure can vary for every car. You can consult the owner’s manual for your car. In general, you can consider the following measurements as normal oil pressure values:
Vehicle Type | While Driving (PSI) | At Idle (PSI) |
---|---|---|
Car | 25 – 65 | 20 – 30 |
Truck | 30 – 70 | 25 – 35 |
If oil pressure falls below these typical values you can consider it as low oil pressure. Similarly, if the oil pressure goes above these measurements this will be regarded as too high.
Whether the oil pressure is too low or high both are concerning as they can lead to several engine problems. So, it is important to pay attention to the oil pressure to get rid of costly repairs or permanent damage.
What is Low Pressure at Idle?
As we discussed earlier, the oil pressure doesn’t remain constant. It varies depending on the speed of the engine. At idle, when the engine is not engaged or the car is not moving, the oil pressure should remain within the range of 20 to 30 PSI. If the oil pressure drops below this threshold the oil pressure is considered too low. This will trigger the warning light on the car’s dashboard.
I would like to mention that the oil pressure at idle depends on many factors including:
- Type of engine
- Condition of the engine
- Viscosity grade of oil
- Engine idle speed
- The operating temperature of the engine
Take this scenario as an example where the engine is cold but the condition of the engine is good. When the engine is cold the oil pressure at idle is higher (40 – 60 PSI). This is because the oil thicker due to cold. As the engine gains temperature, the oil pressure at idle is dropped to 20 to 30 PSI.
What Does Low Pressure at Idle Mean?
Low oil pressure when the car is idling can have several meanings. The least troublesome cause is that there may be a fault in the oil pressure sensor present in the engine. This can be fixed easily by replacing the faulty sensor.
Other reasons that may trigger the warning light are quite worrisome and need immediate action. These include:
- Low oil level in the engine, which may be caused by a leak or damage somewhere in the engine
- Faulty oil pump
- Clogged oil filter
- Improper oil weight / Viscosity
- Poor oil quality