Clean oil is vital to engine performance and durability. It must lubricate, cool and clean the engine as it circulates, but in order to remain effective, it must be filtered as it cycles.

The function of oil filtration is to remove the contaminants introduced into the lubricating oil and prevent them from reaching sensitive engine parts – without restricting normal oil flow to the various points requiring lubrication. Internal sources of contamination include wear products from the rubbing surfaces of the engine, blow-by gases leaking past the rings of the pistons and degradation of the oil itself. A filter must perform well in the areas of

Efficiency is the filter’s ability to capture contaminants. The more efficient a filter is, the more contaminants it will remove from the oil. To make a filter more efficient, the spaces between the fibers in the media are made smaller, creating more resistance and limiting the oil’s ability to flow through the filter. Achieving maximum efficiency along with limited resistance is critical to good filtration.

Capacity is the amount of contaminants a filter can hold and still remain effective. When a filter reaches  maximum capacity, the oil continues to flow through unfiltered, leaving harmful contaminants circulating in the oil. At this point, the filter has reached the end of its usable life and must be changed.

Proper oil flow is essential to keep moving parts lubricated at all times. A filter without adequate flow properties can cause catastrophic engine failure. Flow is restricted as the spacing in the filter media is made smaller to provide

Full-Flow Oil Filtration
Full-flow oil filters install directly into the line of oil circulation; the oil passes through the filter as it travels between the oil pump and the engine. A full-flow oil filter must remove and hold contaminants without obstructing oil flow to the engine. Because they use a thin layer of porous filter paper, most oil filters on the market compromise the filtration of finer materials. Such filters have almost no extended cleaning ability because they have a low capacity for storing dirt. These “surface-type” paper filters quickly become restricted as debris builds up on the surface, at times forcing the filter bypass valve to open and allow unfiltered oil into the engine.

Bypass Oil Filtration
Because oil must be filtered quickly while removing most of the particles, the average full-flow filter traps particles as small as 20 microns. Bypass oil filtration uses a secondary filter with the purpose of eliminating nearly all contaminants in motor oil. Bypass filters have high capacities and eliminate much smaller particles than full-flow filters, including those in the two to 20 micron range, as well as soot and sludge. 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.

Bypass filters operate by filtering oil on a “partial-flow” basis. They draw approximately 10 percent of the oil pump’s capacity and trap the extremely small, wear-causing contaminants that full-flow filters can’t remove. The continual process cleans the oil, reducing long-term wear and helping extend oil life.


AMSOIL Ea Oil FiltersEA15K01
AMSOIL Ea Oil Filters feature advanced full-synthetic media, making them one of the highest efficiency filters available for the auto/light-truck market.

Advanced Media Technology
Cellulose and blended media found in most oil filters have larger fibers than the synthetic media found in Ea Oil Filters. They also have larger spaces between their fibers. This larger space could allow particles to pass through the media and sometimes get caught and plug the media from flowing oil. The smaller fibers in synthetic media have a controlled size and shape, resulting in better durability and greater efficiency and capacity than cellulose filters. AMSOIL Ea Oil Filters provide a higher level of engine protection and extended filter change intervals.

Absolute Efficiency
The exclusive technology used in AMSOIL Ea Oil Filters provides filtering efficiency of 98.7 percent at 20 microns. Ea Oil Filters are among the most efficient filters available for auto/light truck

Maximum Capacity
AMSOIL Ea Oil Filters have greater capacity than competing filter brands, providing confidence the oil filter will provide filtered oil to the engine over the course of the drain interval.



Improved Flow
The synthetic media in AMSOIL Ea Oil Filters allows maximum efficiency without restricting flow. This provides exceptional cold-start performance and ensures consistent oil flow to the engine.

Extended Service Intervals
When used in conjunction with AMSOIL synthetic motor oils, AMSOIL Ea Oil Filters are guaranteed for extended service life:

• Ea Filters designated with product code Ea15K are recommended for 15,000 miles/one year, whichever comes first, in normal or severe service.

• Ea Filters designated with product code EaO are recommended for 25,000 miles/one year, whichever comes first, in normal service or 15,000 miles/one year, whichever comes first, in severe service

AMSOIL Ea Bypass Filters
AMSOIL Ea Bypass Filters provide the ultimate in protection against wear and oil degradation in auto/light-truck, heavy duty and EaHD_350other applications.

AMSOIL Ea Bypass Filters feature a premium two-stage pleated and layered cellulose/full-synthetic media that provides higher filtering efficiency, contaminant removal and increased oil capacity. Ea Bypass Filters feature an efficiency of 98.7 percent at two microns.

When used in conjunction with AMSOIL synthetic motor oil and an AMSOIL Ea Full-Flow Oil Filter, Ea Bypass Filters should be changed every other full-flow filter change up to 60,000 miles, depending on filter size. When used with other brands of motor oil or full-flow filters, Ea Bypass Filters should be changed every other full-flow filter change. AMSOIL recommends using oil analysis when extending oil drain intervals.

AMSOIL offers several bypass filtration systems and Ea Bypass Oil Filters that can be installed on a variety of popular applications, including Ford Power Stroke*, Chevrolet Duramax*, Dodge Cummins*, heavy-duty trucking, off-road and other applications.