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.

One way to think about the importance of correct oil pressure is this: the engine is comprised of many tight spaces and compartments, all of which need to be properly lubricated with oil. When oil flows through the system, the pressure must be high enough that it can force the circulating oil into all of these spaces and coat all surfaces before being circulated back through the system, cooled, and re-filtered.

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. Low pressure will leave areas with less lubrication than necessary, causing friction, increased heat, and engine damage.

High pressure, however, can lead to more heat generation in the engine, which will rapidly degrade the oil while making the engine work harder than it is designed to work.

This can lead to damage as well. This results in friction, warping, seal 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. There are a number of different reasons this could happen, and noticing it right away is an important step towards diagnosing the issue and avoiding future problems.

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.

No matter the reason for your oil loss, it’s important that you contact a professional who can help you mitigate this problem before it becomes an expensive and significant repair.

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.

Remember that the viscosity number will change throughout the year, so if you live in a northern climate and ask the garage what oil they used in January, it might not be the correct oil to put into your vehicle in July.

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 wear at high mileage, which can cause a drop in oil pressure.

This can cause a feedback loop where your high-mileage engine drops below a critical oil level, suffers worse damage, and the damage continues to cause more oil leaking.

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 the 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.

They may be able to come up with a number of solutions such as replacing headers or gaskets that will breathe new life into an old engine.

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, rising engine temperature, and 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.

If you suspect that your oil pressure drop is an issue with your oil pump, do not continue to operate the vehicle. This can lead to major damage to the engine that might go beyond a pump replacement and could ultimately total the engine — an expensive and time-consuming issue.

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.

Your LubeZone mechanic will replace your oil filter with each oil change, so if you are one of our customers, you can rest assured that with regular oil changes, your filter will be working as expected.

How to Diagnose Low Oil Pressure

If you are noticing that your truck is running strangely, something you might want to consider is an issue with your oil pressure. There are a number of different ways to diagnose the issue, depending on the features your truck has:

Check the Oil Level

This is a simple and effective first step to diagnosing your oil pressure issues. Too little oil can keep your engine from building up to the appropriate pressure, and simply refilling to the appropriate level can get you back to normal.

Check Your Instrument Panel

It’s common for newer vehicles to have a warning light, or even a pressure gauge, that will either indicate low pressure or show you the exact pressure in the engine. If your light turns on or your gauge is reading low, it’s time to think about fixing the problem.

Listen for Strange Sounds

You spend a lot of time behind the wheel of your truck, so you probably know the sounds it makes. If you are hearing ticking or knocking in your engine, it might be caused by friction between moving parts due to low oil pressure.

Smell for Burning Oil

If your engine doesn’t have sufficient oil pressure to lubricate your engine, there might be an increase in friction that leads to oil overheating and burning.

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.

You may notice that there are different viscosities available when choosing motor oil. These differences are due to a number of factors, including the tolerance of the pistons and the type of engine you are lubricating, but external temperature is also a very important factor. When oil is cold, it is more viscous, meaning that it does not flow easily. As the engine runs, the oil warms up and begins to flow more freely. If the oil flows too freely when warm, then you might notice a significant drop in oil pressure. If it is too viscous, even when warmed, it can lead to elevated oil pressure. 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.

Fluctuations in oil pressure due to the viscosity will happen multiple times throughout any given drive, so we aren’t looking for exact consistency — what we are looking for is an oil that has the appropriate viscosity for the season. If the oil is either overly viscous or not viscous enough at operating temperature, it can cause serious damage to your engine. Making sure that you have the correct viscosity for your engine and that it is seasonally appropriate is important to ensure the longevity and health of your truck.

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.

How To Choose the Right Oil For Your Vehicle

As you now know, choosing the right oil for your truck is absolutely critical. Here are a few different ways you can make sure you are using the right oil:

Check Your Manual

The manufacturer’s guidelines should always be the first place you look for any recommendations about how to take care of your vehicle. They will give you the exact specifications for the type of oil that will work best in your engine.

Consider Viscosity

The viscosity rating of the oil you choose is very important and may vary depending on the season and average outside temperature. Always make sure that you use the lightest oil recommended by the manufacturer for the best performance.

Explore Types of Oil

These days, full synthetic is typically the best type of oil for a truck because it protects your engine and holds up really well under extreme conditions. You can also choose from conventional and semi-synthetic, where the advantages are typically due to cost savings.

Consult a Professional

If you would rather not have to decide which oil is best for your vehicle, take it to your nearest LubeZone and trust the professionals. We know all about what it takes to keep your truck running smoothly and can take on everyone from oil changes to diagnosing pressure issues and much more.

Low Oil Pressure Stop Engine Light On

When that low oil pressure stop engine turns on, even briefly, it’s a signal that your vehicle needs immediate attention. Oil pressure is critical—it serves as the lubricant for the moving parts within your engine, preventing premature wear that can occur rapidly. Ignoring this warning is akin to overlooking a severe drop in your body’s blood pressure; it’s an issue that demands immediate action.

If your vehicle’s warning light turns off and your mechanic can’t find any errors using diagnostic tools, the situation can be confusing. It’s similar to being declared healthy while experiencing obvious symptoms of an illness.

The problem could be as simple as a defective sensor or a loose connection that triggers the warning inaccurately. Sometimes, sensors can be overly sensitive and react to unpredictable weather conditions. This can cause the diagnostic system to receive intermittent signals that are not reliable.

Another possibility is that there’s an oil problem that isn’t immediately serious enough to trigger a constant warning. For example, low oil levels, substandard oil quality, or a blockage in the oil supply lines may not manifest consistently, similar to a poor internet connection.

Even if your mechanic couldn’t identify any faults, it’s important not to ignore the warning light and continue driving as usual. These indicators can be misleading, like elusive ghost stories. Just because they’re not visible doesn’t mean they aren’t indicative of a deeper issue. Continue your inquiries, consider seeking a second opinion, or request that your mechanic manually verify the oil pressure with a gauge. Detecting an actual pressure issue early can prevent catastrophic engine failure.

Remember, while the cost of car repairs may be unwelcome, the costs of neglecting potential engine problems can escalate dramatically and turn your car into an expensive liability. The best decision is to address the issue promptly to avoid being stranded and making small talk with a tow-truck driver.

Need an Oil Change or Service?

Are you in need of an oil change or check-up, or is your oil warning light on? LubeZone has several locations nationwide ready to help you with your vehicle’s oil change services. Stop by for service today!