So, you notice your oil pressure is low. Your automatic response might be to have your oil pump looked at, or to replace it altogether.
There are quite a few other reasons that can lead to low oil pressure. As you evaluate your particular problem, you might want to consider some of the following as possible causes of your issue.
If you've replaced your oil pump, recently changed your oil, and ensured there were no other issues in the system, there is a chance your oil pressure gauge is malfunctioning. You can have your oil pressure tested, and, if it comes back normal, a sensor replacement should solve your issue.
If your filter is plugged by dirt, debris, or other contaminants, the proper amount of oil won't be able to flow through your engine, decreasing oil pressure. Replacing the clogged filter with a new, clean one should take care of the issue.
Old, worn bearings can create oil pressure issues as well. As your bearings wear, clearance space increases, which increases the amount of oil used. This, in turn, decreases the overall oil pressure.
Contaminants in your oil (coolant, fuel, air, etc.) can alter the oil viscosity and how it flows through your engine. If this seems to be what's causing your engine problems, you'll need to identify the source of the contamination to solve the problem.
Make sure you've checked the oil levels in your engine. If your pressure is low, you might simply have to put in more oil.
If your engine is consuming large amounts of oil, you may have a larger engine problem.
6. IMPROPER INSTALL
Even if your oil pump is new, if it wasn't installed correctly, you'll still be experiencing problems.
We have an earlier post that details various ways a poorly installed oil pump can cause you trouble. If you're experiencing low pressure after installing a new pump, verify that it has been installed correctly.
7. ENGINE AGE
Similar to worn bearings, an older engine will consume more oil, leading to a decrease in oil pressure. In some cases, you'll need to completely rebuild your engine.
Sometimes, we hear operators complain that they're still experiencing poor oil pressure after rebuilding their engine. Ideally, a rebuild would help fix this, but a few factors might prevent it.
Improper break-in, for instance, could cause low oil pressure. Similarly, not following proper oil change procedures could negatively impact your oil pressure.
To learn more about these, check out our Diesel Engine Break-in Guide.
Experiencing low oil pressure? It might be time to consider a new oil pump. We have ASE Certified Technicians on staff who can help you get the right parts for your diesel engine.
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Originally Posted January 2, 2019; Updated February 17, 2021