What Causes Low Oil Pressure?

Seeing a warning light come on indicating your engine has low oil pressure could mean you have a serious problem.

Having the right oil, along with the correct level of oil and oil pressure is essential for an engine to run optimally. If the pressure drops too much, an engine can be damaged beyond repair in a matter of minutes.

To potentially save yourself a huge repair bill and an even bigger headache, it’s a good idea to familiarize yourself with what oil pressure is, why it’s important, some of the common causes of low oil pressure problems, and what to do in the case of an emergency.

Importance of Oil Pressure

Oil pressure is one of the most important factors contributing to an engine running smoothly and lasting a long time.

Engines are complex pieces of machinery, and they have a lot of weight to pull – literally. Having oil in an engine makes sure that all the moving parts are well lubricated and able to function optimally.

When the oil is flowing through an engine, pressures build up. It’s this pressure that ensures the oil reaches everywhere it needs to and keeps on flowing.

If the pressure drops to the point where oil is no longer flowing freely around all the engine’s moving parts, unlubricated metal surfaces will come into contact.

This results in friction, warping, seals breaking, and some other issues. In short, it’s a quick way to ruin an engine. Problems with oil can truly inflict major damage to your vehicle if left unchecked.

So, it’s essential that you keep an eye on your oil pressure gauge and conduct routine maintenance. If the warning light comes on to indicate there is a problem with the pressure, stop your vehicle as soon as possible.

To give an idea of what the problem might be, here are 5 of the common causes of low oil pressure in your engine:

5 Causes of Low Oil Pressure

There are many possible causes behind low oil pressure, some more obvious than others.

If your oil warning light is on and you want to perform some checks yourself, the following information should help:

1. Oil Level Is Too Low

The oil level dropping below the minimum dipstick line is one of the most common causes of low oil pressure. This can happen at any time, even if you’ve recently had an oil change.

Over time, engines burn oil more quickly. This is due to piston rings wearing, seals leaking, and so on. Or, you may find you actually have an oil leak. So, you may see a faster drop in oil pressure depending on the age and condition of your vehicle.

This is most likely the case if you discover your oil level is too low despite recently having your oil topped off, as you wouldn’t expect it to suddenly be burning quickly.

What to do – Check your oil level. If it’s below the recommended minimum amount, top it off. Check for leaks by looking for oil drops on the floor and monitor how many miles before you need to top off again.

2. The Viscosity of the Oil Is Too High or Too Low

Oil viscosity relates to how easily the oil flows around the engine at any given temperature. If the oil’s viscosity in your engine is wrong, it can register as low oil pressure.

High viscosity oil will typically produce greater resistance, while low viscosity has the opposite effect. Typically, lower viscosity oils are used in colder temperatures while in the summer when temperatures rise, a higher viscosity oil is often used. All engine oils come with a grade and viscosity rating. It’s important to check your car’s manual to identify the right oil for your vehicle.

What to do – If you’re topping off your engine oil yourself, check with the manufacturer’s handbook that you’re using the correct oil. If a garage did the oil change, ask them what oil they used.

3. Signs of Engine Wear

If you check your dipstick and it says you have enough oil and you’re sure it’s the correct viscosity, it might be a sign that your engine is starting to wear.

There are a number of moving parts in an engine that oil has to flow freely through. In particular, the engine bearings are prone to wearing at high mileage, which can cause a drop in oil pressure.

Many factors contribute to how long an engine will run before showing signs of wear and burning oil quicker. As a general rule of thumb, you should be proactive in maintaining engine health of cars or trucks that are used frequently.

What to do – You need to have your engine checked by an engine technician to establish if worn engine parts are the cause.

4. Oil Pump Failure

The oil pump is what regulates semi-truck oil pressure. If the pump is malfunctioning in any way, one of the first things that will happen is your low oil pressure warning light will come on.

You may also notice decreased power, your engine temperature rising, and the engine stalling.

What to do – You will need to have your pump checked by a mechanic to confirm if this is the cause or not.

5. Clogged or Dirty Oil Filter

Oil filters help to remove contaminants, dirt, and other debris from engine oil. These particles can build up over time, and without a filter, would cause serious damage to an engine.

Filters can only hold so much before they need replacing. If your filter is starting to get clogged up, less oil will flow around the engine, causing the pressure to drop.

What to do – Have your oil filter checked by a mechanic and replaced if necessary.

What Is Normal Oil Pressure on a Semi-Truck?

The exact range will vary depending on the type of engine you have. For most semi-trucks, the normal operating oil pressure is between 40-50 PSI (pounds per square inch).

Keep in mind that it takes around 20 minutes for an engine to reach its maximum operating temperature. The pressure will also drop a little if you’re spending a lot of time idling, too.

Trucks are fitted with both an oil pressure gauge, showing the oil pressure in PSI, and a warning light should the pressure drop dangerously low.

It’s always important that you pay attention to any warning lights on your dashboard. The oil pressure is one of the most serious. If the light comes on, or you see the pressure dropping on the gauge, act as soon as possible.

Understanding Oil Viscosity

When discussing oil and how engines work, it’s important to get a good understanding of what viscosity means and how it affects semi-truck oil pressure.

Viscosity refers to how ‘fluid’ a liquid is and how it reacts to pressure. It’s a way of measuring the force per unit area resisting flow.

In simple terms and looking at engine oil specifically, oil’s viscosity determines how freely the oil can flow around the engine and lubricate it.

This means having the right viscosity is essential for an engine to run optimally. It’s important to remember, too, that engines can run in the range of 195-200 degrees Fahrenheit.

So, you need an oil that is equipped to operate when cold as well as the maximum operating temperature of the engine it’s being used in.

If you look at the shelves in a vehicle servicing workshop, you’ll see dozens of different oil types, all displaying different viscosity ratings. It’s essential you find out which oil is the correct one for your vehicle and only use that recommended oil grade.

Need an Oil Change or Service?

In need of an oil change, check-up, or have your oil warning light on? Search for “semi-truck oil change near me” and you’re likely to find us somewhere in your area. With several locations nationwide, we’re here for you. Stop by for service today!