Heavy Duty Bypass Oil Filtration System

Bypass Kit for Over the Road Trucks and large capacity motors

High Capacity BMK-30 The AMSOIL Heavy-Duty By-Pass Filtration System (BMK30) provides superior filtration performance for heavy-duty on- and off-road applications. It's designed specifically for the Heavy-Duty Ea By-Pass Filter (EaBP120), bringing Ea synthetic nanofiber technology to the heavy-duty market.

SKU: BMK30 Category:

High Capacity BMK-30

The AMSOIL Heavy-Duty By-Pass Filtration System (BMK30) provides superior filtration performance for heavy-duty on- and off-road applications. The BMK30 is designed specifically for the Heavy-Duty Ea By-Pass Filter (EaBP120), bringing Ea synthetic nanofiber technology to the heavy-duty market.

“Our customers are amazed how simple these actually are thus their low price. Advanced nano-fiber media and a high quality mounting kit with high strength hose fittings. Just call and estimate the total feet of hose you need and we’ll have your kit on the way!”

Buy and Pricing

Note: The EaBP90, EaBP100, and EaBP110 spin on filters will not work with this kit. Filter and hose not included with the BMK30 kit. The EaBP120 Filter is the required filter and hose (BP250) must be purchased separately. Some installers use their own hose

See Bypass Installation Samples

Instructions and other documents found at the links below.

Bypass Basics
Bypass oil filtration features a secondary filter with the purpose of eliminating nearly all contaminants from motor oil. Bypass filters have high capacities and eliminate much smaller particles than full-flow filters, including soot. Bypass filters 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 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. It is called Bypass filtration because the oil flows from the bypass filter back to the sump and Bypasses the engine. This continual process eventually makes all of the oil analytically clean, reduces long-term wear and can dramatically extend drain intervals.

AMSOIL Heavy-Duty Bypass Filtration System
The AMSOIL Heavy-Duty Bypass System includes all necessary hose-end fittings and mounting bolts, but the filter, hose and engine adapter must be purchased separately. The hose and engine adapters are not included due to the kit’s high variability of application, resulting in varied mounting locations, hose lengths and engine adapter sizes. Prior to installation, determine where the filter mount will be located and how much hose will be necessary to complete the installation. The installer must also determine the size of the high- and low-pressure ports in order to determine which engine adapters to purchase. Hose is available by the foot from AMSOIL (BP250), and adapter fittings can be purchased from any hydraulics or heavy-duty equipment outlet.

High-Quality, Durable Construction
The Heavy-Duty Bypass System is constructed of high-quality cast aluminum with a steel filter spud that has been thoroughly tested in on-road and severe off-road service. The mount is finished with a thick layer of powder-coated paint to provide maximum resistance to the degrading effects of road salt, debris and engine-compartment chemicals.

Compatible with Very Large Engines
Heavy Duty Bypass Oil Filtration Systems can be plumbed in a series to provide maximum filtration protection for large V12 and V16 engines. The filter mount features a 3/8 NPT connector that connects the outlet and inlet of adjacent filter mounts. For more information on engine adapters or the installation of multiple Bypass systems on one application, contact AMSOIL Technical Services at (715) 399-TECH.

General Installation Guidelines
Determine the location of a pressurized oil port on the engine. Pressure ports are usually found on the main oil galley or in close proximity to the full-flow filter head assembly. The oil flow from this source should be plumbed into the inlet side of the filter mount. The outlet will be directed to a low-pressure point on the engine, typically a port located at or near the oil pan. Detailed instructions are included with the Heavy-Duty Bypass System kit.

The AMSOIL Heavy-Duty Bypass Filtration System saves money by enabling the installation of an AMSOIL Ea Bypass Filter. Its heavy-duty design is ideal for equipment subjected to extreme conditions. The ability to mount the system remotely allows the equipment operator to more easily change filters, adding convenience and reducing the amount of time necessary to perform routine maintenance.

AMSOIL Ea Heavy-Duty Bypass Filter
The AMSOIL Ea Heavy-Duty Bypass Filter features the same full-synthetic media as the rest of the Ea Bypass Filter family. It removes 98.7% of all contaminants two microns or larger (ISO 4548-12), and provides superior soot-removal efficiency at less than one micron. It comes complete with a marine powder-coated finish for long filter life, even in extreme conditions.

Increased Oil Capacity
The Ea Heavy-Duty Bypass Filter increases the fluid system capacity by approximately one gallon, depending on length of hose and distance the filter is mounted from the engine. The additional oil and extended filtration life provide improved oil cooling and ensure equipment constantly runs on clean oil. Engine efficiency is increased, providing extended engine life.

Extended Service Life
AMSOIL recommends changing the Ea Heavy-Duty Bypass Filter every other full-flow filter change up to 90,000 miles. Extended oil drain intervals should always be accompanied by an oil analysis program.

Heavy-Duty Filtration
The Ea Heavy-Duty Bypass Filter was designed for heavy-duty applications. Its robust construction and superior filtration performance provide maximum protection over extended drain intervals, reducing downtime, increasing equipment life and saving money.

  • Extended drain intervals
  • Improved oil cooling
  • Increased filtration capacity and life
  • Increased fluid system capacity
  • Efficient small particle and soot removal
  • Extended engine life
  • Maximum engine efficiency
  • Removes particles less than one micron
  • Convenient spin-on design

The AMSOIL Heavy-Duty Bypass System and Ea Heavy-Duty Bypass Filter provide maximum filtration performance for virtually all heavy-duty diesel applications, including Class 6, 7 and 8 heavy-duty trucks, off-road equipment, buses, generators, marine engines, logging and agricultural equipment.

Installation photos from a customers Detroit Diesel  – Customer is VERY pleased with the results and AMSOIL’s DEO 5W-40 in service for extended intervals.


AMSOIL products are backed by a Limited Liability Warranty. For complete information visit www.amsoil.com/warranty.aspx.

Buy and Pricing


Leave a Reply