A Closer Look at Bypass Filter Systems

Watch the AMSOIL bypass filter system remove particles down to 2 microns for maximum protection.

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AMSOIL Bypass Oil Filter Systems
by Joel Youngman
March 9, 2022

Bypass oil filter systems feature a secondary filter with the purpose of eliminating nearly all contaminants from engine oil. Bypass filters have high capacities and eliminate much smaller particles than full-flow filters. They reduce engine wear and increase oil volume, but their high efficiencies mean they also have higher restriction and must be used in conjunction with a full-flow filter.

How A Bypass Filter System Works

Bypass filters operate by filtering oil on a “partial-flow” basis. They draw approximately 5% of the oil pump’s capacity at any one time and trap the extremely small, wear-causing contaminants that full-flow filters can’t remove.

Bypass filters have a high pressure differential, causing the oil to flow through them very slowly and allowing for the removal of smaller contaminants, including soot.

It is called bypass filtration because the oil flows from the bypass filter back to the sump, bypassing the engine. This continual process eventually makes all the oil analytically clean, reduces long-term wear and can extend oil drain intervals.

AMSOIL Bypass Filter System Benefits

Significantly Extended Engine Life

The majority of engine wear is caused by particles in the 5-20 micron range. Because AMSOIL Bypass Filters effectively remove contaminants down to 2 microns, engines receive the ultimate in wear protection. Less engine wear keeps the engine in better condition, extending its life.

Efficient Small-Particle and Soot Removal

The high-efficiency AMSOIL Bypass Filter element is 98.7% effective at removing particles down to 2 microns, helping extend engine life. It is also a very effective soot-removal device.

Reduced Maintenance Costs

AMSOIL bypass filter systems provide a dramatic increase in engine protection, helping avoid costly repairs associated with engine wear.

Improved Oil Cooling

By installing an additional filter, the engine system has the capacity to hold more oil. With increased oil capacity, the oil filtration system contains more fluid through which it can disperse heat from the engine. This allows the engine and the oil to run cooler.

Extended Drain Intervals

AMSOIL Bypass Filters can help users extend their oil drain intervals. Make sure to use oil analysis when extending oil drain intervals.

Easy Installation

AMSOIL Bypass Oil Filter Systems are relatively easy to install and easy to maintain for most enthusiasts with a little mechanical know-how. Do-it-yourself installation instructions are provided with each kit.

Check out this post to watch how to install a bypass filter system.


Durable Construction

AMSOIL Bypass Systems and Bypass Filters are built tough to withstand the most severe operating conditions. They provide long life even in tough driving and operating conditions.

by Joel Youngman

AMSOIL Lead Technical Writer for more than two decades.

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AMSOIL Bypass Oil Filter Systems

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