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The Reasons Behind High Oil Pressure

If you are experiencing high oil pressure frequently or even regularly, it is about time you asked for help.

Even though oil pressure in a car should ideally be at a medium level, it is not uncommon for it to surge. Chances are your engine will need serious repair, if not replacement is in your near future.

There are several commonly known causes of high oil pressure in vehicles. We will list them and briefly discuss each.

What Causes High Oil Pressure

A Blocked Oil Passage

A blocked oil passage can cause serious damage to your engine. If the passage remains blocked for a long period of time, it denies the necessary oil lubrication to the engine. A clear sign that a blocked oil passage is causing a problem could be an oil leak at the cam assembly. Another name for this leak is lifter tap.

In any case, cleaning a blocked oil passage can be an arduous and high-priced task. Therefore, car-repair amateurs should avoid doing it.

A Faulty Oil Sending Unit

This malfunction is what causes high oil pressure in vehicles most often. You can assume that your oil sending unit is faulty if your gauge constantly reads abnormally high or low levels of oil pressure. Moreover, a sporadic and seemingly random blinking of your oil light might be a sign of trouble.

oil sending unit
oil sending unit location
Image credits Briansmobile1:

Now, troubleshooting your oil sending unit requires a multimeter. Turn it to the resistance range and see if your result is 240 ohms. If it isn’t, your oil sending unit is the culprit.

A Broken Pressure Relief Valve

While pressure relief valves do not usually get stuck, they can malfunction occasionally. Now, the trouble is that you cannot troubleshoot a valve while it is working. What you need to do is remove it, clean it, and put it back in the engine.

In case the oil pressure reading remains unchanged, you need to look for the cause of the problem somewhere else. However, if the pressure reading returns to normal, you solved your problem.

A Dirty Oil Filter

blocked oil filter

Clearly, a dirty filter cannot supply enough oil to the engine. Filth and debris accumulate and eventually clog the filter. This can lead to an increase in the temperature, which in turn can cause high oil pressure.

To clarify, if this is the cause of your troubles with high oil pressure, you are lucky. There will be no need for replacing the filter. You’ll just have to take the oil filter out and give it a thorough cleaning.

Idling Pressure

Idling often causes high oil pressure due to high temperatures in an idle engine. Technically, the oil needs to be heated up in order to flow easily. Therefore, it is only on rare occasions that idling causes high oil pressure.

Oil Quality

pouring engine oil

Choosing an oil with the wrong viscosity can affect the overall oil pressure in your vehicle. For example, the occurrence of high oil pressure upon oil replacement might mean that the oil you are using is too thick. The reason for this is that the oil is simply too thick to reach every part of the engine.

Miscellaneous Causes

Other reasons for high oil pressure might involve a damaged oil pump or worn bearings. Either way, a simple replacement process should suffice in solving the issue.

Final Thoughts

As mentioned before, if you are experiencing high oil pressure regularly, you should consult with a mechanic. By doing so, you might be able to avoid replacing the engine altogether. Hopefully, you will not need this kind of repair. However, we hope that this article gave you at least an idea of what causes high oil pressure. After reading this, you should be able to identify the source of the problem.

In any case, keep in mind that any damage to any part of the oil sending unit can be the cause of the problem. Aside from what we listed, there is a number of other possible answers to the question of what causes high oil pressure. In order to avoid it altogether, make sure you replace the oil regularly. Remember to always choose the oil brand appropriate for your car’s engine and to clean the oil filter frequently.


Richard Reed
I've been a General Manager of a moving company and I've also been a Professional Mover for over 30 years. I've driven flat beds, reefers, dropdecks, moving vans, heavy machinery, etc. In my time as a Mover I've driven over 1,000,000 safe miles. My days of moving and driving truck are past me but The Vehicle Lab allows me to share the knowledge I've gained over the past 40 years.

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