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Causes of Low Oil Pressure in Engines

Low oil pressure in an engine can disrupt performance, lead to overheating and friction between moving parts, and eventually cause the engine to stall. Learning more about the common causes of low oil pressure in different environments can help you protect your engines from damage – and reduce the risk of costly repairs and replacement.

Learn more about why maintaining proper oil pressure levels is important and what can cause low oil pressure in vehicles.

Why Oil Pressure Is Important

While many factors determine the lifespan of an engine and how well it performs, having the right oil pressure is one of the most important. Engines have a lot of moving parts and can generate a lot of heat. These moving parts require sufficient lubrication to eliminate the risk of premature wear and to keep engine temperatures in an appropriate range.

However, it’s not enough to just supply the engine with oil; that oil must also be at sufficiently high pressure to coat all the moving parts of the system. Once there’s not enough pressure, the oil won’t reach all the surfaces, leading to metal-on-metal contact, damaging friction and high temperatures. Left untreated, low oil pressure levels can also break seals in the engine and cause significant damage to other components.

Vehicle operators and maintenance technicians can stay on top of potential oil pressure issues with regular inspections and maintenance. Vehicles have a pressure gauge that automatically monitors pressure levels and turns on an indicator light as soon as oil pressure drops, at which point drivers should immediately halt the vehicle and resolve the issue before continuing to drive.

What Causes Low Oil Pressure?

You can troubleshoot each of the four common underlying causes of low oil pressure to discover which is to blame.

Not Enough Oil in the Engine

Oil needs to be regularly replaced and replenished to keep vehicles running smoothly. Some of the reasons why oil levels can decrease over time include:

  • Leaks in the oil plug or seals
  • Evaporation, causing faster-than-normal oil consumption
  • Burning, due to worn piston rings

Adhere to a strict oil replacement schedule and regularly assess oil levels to prevent this cause of low oil pressure. As engines age, their oil consumption naturally increases, so it is normal to refill more often as time goes on. However, make sure there are also no oil drops or leaks evident on the ground below the vehicle, as this indicates leaking components that must be fixed.

Too High or Low Viscosity

Oil comes in many different viscosity levels, which determine how easily it will flow throughout an engine at certain temperatures. Different vehicles will require different types of oil, so the vehicle’s manual will say the manufacturer’s recommended oil viscosity rating and grade. In general, high-viscosity oil is thicker and produces more resistance, while low-viscosity oil is thinner with less resistance. High-viscosity oil is typically used in summer months or warmer temperatures, while low-viscosity oil is used in colder temperatures.

If the wrong oil viscosity is used, the engine may register it as low oil pressure even though the oil has been properly replenished. The best way to prevent this potential cause is to double-check that the right oil is being used for the specific make and model of the vehicle (and the season or climate at hand). Mechanics should also be able to confirm which oil they used if the vehicle was taken to a shop for an oil change.

Engine Wear

Sometimes, the underlying cause is engine damage. First, check the dipstick to rule out the possibility that the wrong type of oil or oil level is being used. If both are correct, the low oil pressure warning could be indicating that components of the engine itself are worn. Engine bearings can wear down if the vehicle operates at high speeds. Older, frequently used cars will experience engine wear more quickly.

To address this potential cause, a trained mechanic should inspect the engine for signs of wear. Regular maintenance can also reduce the risk of engine wear.

Defective Oil Pressure Gauge

If you’ve already checked for all of the above potential causes and the low oil pressure light is still on, it may be a sign that the oil pressure sensor itself is defective. If, even after replacing the sensor, the low oil pressure warning still comes on, it could be due to a faulty oil pump.

Industries Where Lubricants Are Most Affected by Cold Weather

Some industries need to store and use lubricants outside, where cold temperatures can negatively impact their effectiveness. This commonly applies to the mining, agriculture, transportation, oil and gas, and water treatment industries.

Freezing temperatures increase the viscosity of oil-based fuels and lubricants. While they don’t freeze solid, they become thicker until they resemble wax. Under 15°F (-9°C), the wax in the lubricant or oil starts to crystallize, separating from the oil. In this state, it is very difficult to remove the oil from the container.

Insulating fuel pipes that carry fuel oils can mitigate the risk of freezing, separating and clogging. It’s also helpful to know the freezing temperatures for different gear oils, motor oils and hydraulic oils. Thin motor oils like 10W30 varieties start to thicken at 50°F (10°C) and will freeze at -20°F (-29°C), while hydraulic and gear oils freeze at -10°F (-23°C). But higher-viscosity oils like 15W30 are designed to stay fluid until temperatures drop to -55°F (-48°C).

Turn to Lubrication Engineers to Learn More About Engine Oils

The team at Lubrication Engineers is here to help our customers with information about engine oils and expert guidance in keeping systems in good repair. Learn more about engine oils so you can protect your vehicles and industrial systems.

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