BMK-30 Heavy Duty Bypass Filter Kit

BMK-30 Complete with 15 feet of hose and filter.
Complete with 15 feet of hose and filter.

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 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!

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Printable Data Bulletin PDF

Fitting List

Fitting List – Find out where to tap on your engine and where to return!! Save and Print.bypass filter for rigs - fitting guide

Install Instructions
Instructions – These are the exact instructions included in the kit.

Call 800-579-0580 for best price and ordering!

Heavy-Duty BMK-30 Remote Filtration System and Ea® Bypass Filter combine to provide outstanding oil filtration efficiency

Bypass Basics

Bypass oil filtration introduces 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, including soot. Bypass filters reduce engine wear through high filtering efficiency, which means they 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 cleans all the oil in the system, reduces long-term wear and can dramatically extend the life of the engine.

AMSOIL Heavy-Duty Bypass System

The AMSOIL Heavy-Duty Bypass System includes the mount, mounting hardware, 15 feet of hose, hose fittings, installation instructions and Bypass Filter (EaBP120). Available separately, the oil sample valve (BK30) eases the process of collecting oil samples. The system provides most of the necessary fittings, except the fitting required to pull pressurized oil from the engine and the return fitting to return oil to the sump. Other parts and fittings can be purchased from any hydraulics or heavy-duty equipment outlet.

High-Quality, Durable Construction

The Heavy-Duty Bypass Filtration 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.

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 Filtration System.

AMSOIL Ea® Heavy-Duty Bypass Filter

The AMSOIL Ea Heavy-Duty Bypass Filter (EaBP120) features a proprietary media that removes 98.7% of all contaminants two microns or larger (ISO 4548-12), and provides superior soot-removal efficiency. 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 highly filtered oil. Engine efficiency is increased, providing extended engine life.

Extended Service Life

The Ea Heavy-Duty Bypass Filter offers long service life. Do not exceed the limits listed in the chart below. 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.

  • Significantly extended engine life
  • Efficient removal of small particles and soot
  • Removal of particles two microns and larger
  • Increased engine efficiency
  • Improved oil cooling
  • Helps maintain oil viscosity
  • Reduces unscheduled downtime
  • Reduces operational costs
  • Increased fluid system capacity
  • Increased filtration capacity and life
  • Environmentally friendly
  • Extended drain intervals


The AMSOIL Heavy-Duty Bypass System and Ea Heavy-Duty Bypass Filter provide maximum filtration performance for virtually all heavy-duty gas and diesel applications, including Class 6, 7 and 8 heavy-duty trucks, off-road equipment, buses, generators, marine engines, logging and agricultural equipment. This bypass filtration system can be plumbed in series for larger applications with large sumps. For more information about the installation of one or more heavy-duty bypass systems on your application, contact AMSOIL Technical Services at (715) 399-TECH.

AMSOIL products are backed by a Limited Liability Warranty. For complete information visit

OIL ANALYZERS INC., 715-395-0222, is a division of AMSOIL that provides cost-effective, quality oil analysis services.

Install Tip

Attach the unit to a steel panel then just hook on the panel to the frame:
Saw a Detroit owner simply cut a steel panel (Aluminium or wood would work too)  about as long as the whole unit and slightly wider – he then drilled four oval slots at the top and bottom to easily mount to any frame using J-Bolts. This makes it a fast attachment and you can easily adjust to your needs without drilling any permanent holes. 

In addition:
Custom Install for 2011 Freightliner – See below for details.

Amsoil heavy duty oil bypass filter kit BMK-30 installed

The AMSOIL Heavy-Duty By-Pass System (BMK30) was installed on this 2011 Freightliner Classic. It features a custom-built 2003 Series 60 Detroit Diesel 12.7L engine that makes 500 hp. It is a Glider Kit, which is essentially a new truck with a remanufactured engine, transmission and rear ends. A 1/4-inch bracket was bolted to the frame using existing holes to avoid drilling new holes. We located the bracket as close to the engine as possible to minimize the amount of hose required.

The oil supply line taps into the oil filter housing, which has several oil galley plugs for that purpose. The oil return line attaches to a galley plug in the oil pan, where most engine manufacturers include galley plugs. The entire installation took about 90 minutes and used aftermarket hoses and fittings throughout. The truck uses 12 gallons of AMSOIL Premium Protection 20W-50 Synthetic Motor Oil (it is not equipped with EGR or a DPF). AME 10W40 is suggested) We also installed a Sample Valve Kit (BK30) for drawing oil samples for oil analysis.

AMSOIL By-Pass Filter Replacement Chart
Type of Unit Stock Number Size (Approx.) Additional Oil Needed Crankcase Capacity Applications

(Used with BMK30
Heavy-Duty By-Pass System)

(1) EaBP120 Width = 5.35 in.
Length = 12.12 in.
Height = 17.5 in.
4 qt. 15 to 42 qt. Large Trucks, Construction, Farm and Industrial Equipment, (minimum sump capacity = 15 qt.), the BMK30 kit can be mounted in series for sump capacities greater than 42 quarts.
Normal Service Life b:When used in conjunction with AMSOIL motor oil and an EaO or Donaldson Endurance filter, EaBP Filters should be changed every other full flow filter change up to 60,000 miles. When used with other brands of motor oil or full flow filters, the EaBP filter should be changed every other full flow filter change. AMSOIL recommends using oil analysis when extending oil drain intervals.

a. Filters can be used on sumps of larger capacity but then require more frequent replacement. Full details on service life included with filter installation instructions.

b. Data determined in a non-turbo gasoline engine with AMSOIL 100% Synthetic Motor Oil and AMSOIL Ea Full-Flow Oil Filter. Service life varies in other engines (turbo and diesel) and with other
oils and filters.

1. Special adapters and hardware may be required for some installations.
2. Contact AMSOIL INC. Technical Services for instructions before installing on vehicles with cast aluminum oil pans. Call 715-399-TECH (8324)

Other Units Available:

Vehicles with sump capacities up to and including 15 qts
Mount Filter
BMK21 Single Universal (Filters sold separately) Any size AMSOIL Ea By-Pass Filter Element
BMK23 (Filters and spin-on adapter sold separately) Any size AMSOIL Ea By-Pass Filter Element, and 3/4″-16 thread EaO filter as room permits
BMK25 Cummins Diesels (2004 and earlier only)
(Filters and spin-on adapter included)
EaO26 and EaBP100 Ea By-Pass Filter Element
BMK26 International Diesels
(Filters and spin-on adapter included)
EaO26 and EaBP100 Ea By-Pass Filter Element
BMK27 Duramax Diesels (in GM Pick-ups)
(Filters and spin-on adapter included)
EaO26 and EaBP100 Ea By-Pass Filter Element
Vehicles with sump capacities greater than 15 qts
Mount Filter
BMK22 Dual Gard (Hose and filters sold separately) Any size AMSOIL Ea By-Pass
(mount requires 2 filters)
BMK30 Dual Gard (Hose and filters sold separately) EaBP120 Ea By-Pass Filter Element

Simple Bypass system on Freightliner Columbia.

Amsoil is the best for your non-DPF truck.

This link takes you to the AMSOIL Bypass Filter Kit section where you can find additional kits for other vehicles – Attach these filters and kits to any vehicle!