Why Is Your Truck Losing Oil Pressure?

Low oil pressure is a critical failure on any internal combustion engine. When oil pressure to your engine falls too low, internal parts lose essential lubrication and cooling, leading to rapid and premature wear. Driving a truck with low oil pressure for long can cause the engine to seize entirely, ultimately forcing you to deal with a costly rebuild or replacement.

Unfortunately, low oil pressure conditions aren't uncommon on older rigs. Assuming you don't have a massive leak running your oil dry, there are numerous potential causes. This article will discuss three common problems that can result in a loss of oil pressure in your truck.

1. Oil Dilution or Contamination

Your truck's engine relies on a certain thickness (or viscosity) to effectively move oil through the system and coat internal parts. Oil that's too thick or too thin won't flow correctly and may ultimately trigger a low oil pressure warning. As a result, your first step when diagnosing any oil pressure issue is to pull your dipstick and check the condition and level of your oil.

If your oil level is too low, that's most likely the immediate cause of the problem. However, oil that appears very thin or translucent may indicate a dilution or contamination problem. This situation is especially likely if you notice that your oil level is also too high. Replacing contaminated oil is critical, but you'll also need to determine the cause of fuel or coolant entering your oil system.

2. Faulty Oil Pressure Sensor

Your oil pressure sensor is what triggers your low oil pressure warning light. Of course, this sensor is not immune to faults. A failing sensor can produce low oil pressure warnings even when everything is fine with your engine, potentially causing you to waste time chasing down oil-related issues that don't exist.

Experienced technicians will use a separate gauge to test your truck's oil pressure to avoid this situation. By comparing the gauge readings to your truck's oil pressure readings, they can determine if the sensor's data appears accurate. If the results differ, replacing the sensor is usually a cheap and easy fix for your warning light.

3. Stuck Oil Pressure Relief Valve

While low oil pressure is dangerous, high oil pressure can also damage your engine. The oil pressure relief valve helps to alleviate this condition by regulating your truck's oil pressure. This valve typically comes into play when your oil viscosity is unusually high, such as during cold starts on frigid winter mornings.

A stuck valve may allow oil to bleed at all times, preventing your truck's engine from reaching its nominal oil pressure level. If you notice that your rig cannot seem to reach operating pressure at all, it may be due to a stuck relief valve.

For more information about semi truck repair, contact a local auto shop.