AMSOIL HEAVY-DUTY BYPASS SYSTEM

The AMSOIL Heavy-Duty Bypass System (BMK30) delivers maximum filtration performance for heavy-duty diesel and gasoline engines, removing contaminants that standard full-flow oil filters leave behind. It is built for operators who run Class 6, 7, and 8 trucks, off-road equipment, buses, generators, marine engines, and agricultural machinery where engine longevity and reduced maintenance costs matter most.

Heavy-duty engines operate in punishing environments. Diesel soot accumulates rapidly, fine wear particles circulate continuously, and standard full-flow filters are limited by design. A full-flow filter must balance flow restriction against filtration efficiency, which means particles smaller than about 20 microns routinely pass through and continue to cause abrasive wear inside the engine. Over hundreds of thousands of miles or thousands of operating hours, that constant abrasion shortens engine life and drives up rebuild costs.

REMOVES PARTICLES DOWN TO 2 MICRONS
The AMSOIL Heavy-Duty Bypass Filter (EABP120) features a proprietary media that removes 98.7% of all contaminants 2 microns and larger, tested per ISO 4548-12. That level of filtration captures soot, fine metallic wear particles, and other contaminants that full-flow filters simply cannot trap. For context, a typical full-flow filter is rated at 20 to 25 microns. The bypass filter works alongside the full-flow filter on a partial-flow basis, drawing less than 5% of the oil pump's capacity at any one time, filtering it thoroughly, and returning it to the sump. Over time, this process cleans all the oil in the system repeatedly, keeping contamination levels far lower than a full-flow filter can achieve alone.

IMPROVED OIL COOLING AND INCREASED SYSTEM CAPACITY
Installing the Heavy-Duty Bypass System adds approximately 1 gallon of oil capacity to the engine's fluid system, depending on hose length and mounting distance from the engine. More oil in the system means more thermal mass to absorb and dissipate heat. The additional oil and extended filtration life work together to keep the engine running on highly filtered oil at lower temperatures. For trucks running Cummins ISX, Detroit DD15, or Cat C15 engines in long-haul applications, or for Powerstroke and Duramax pickups pulling heavy loads, that added capacity translates directly to cooler oil and longer component life.

EXTENDS OIL DRAIN INTERVALS WITH OIL ANALYSIS
When paired with an oil analysis program, the AMSOIL Heavy-Duty Bypass System supports extended drain intervals up to 120,000 miles, 1,800 hours, or 1 year, whichever comes first. The bypass filter element (EABP120) should be replaced at those same intervals. Extended drain intervals should always be verified through oil analysis to confirm oil condition. For fleet operators running Class 8 trucks on the highway, or contractors logging hours on off-road equipment, fewer oil changes mean less downtime, lower disposal costs, and reduced maintenance labor.

DURABLE CONSTRUCTION FOR SEVERE SERVICE
The bypass filter mount is constructed from high-quality cast aluminum with a steel filter stud, tested in both on-road and severe off-road service. The mount is finished with a thick layer of powder-coated paint to resist road salt, debris, and engine compartment chemicals. The system comes complete with the mount, mounting hardware, 15 feet of hose, hose fittings, installation instructions, and one AMSOIL Bypass Filter (EABP120). The fitting required to pull pressurized oil from the engine and the return fitting to the sump are application-specific. Fitting suggestions and fitting locations for specific engines are available through the BMK30 Fittings List on the AMSOIL website. Additional fittings can be sourced from any hydraulics or heavy-duty equipment outlet.

HOW BYPASS FILTRATION WORKS
Bypass filtration is a secondary filtration circuit that operates in parallel with the engine's full-flow filter. Oil is drawn from a pressurized port on the engine, routed through the bypass filter housing at low flow rates, and returned to the oil pan. Because oil flows through the bypass filter very slowly, the media can trap extremely small particles without creating the flow restriction that would starve the engine of oil. This is not a replacement for the full-flow filter. It is a complement to it. The full-flow filter handles high-volume filtration of larger particles at full engine flow, while the bypass filter continuously polishes the oil by removing the fine contaminants that cause long-term wear. Soot particles smaller than 2 microns can still darken the oil, but the oil's dispersant additives keep those sub-micron contaminants in suspension to prevent agglomeration and wear.

APPLICATIONS AND COMPATIBILITY
The BMK30 system fits virtually all heavy-duty diesel and gasoline applications, including Class 6, 7, and 8 heavy-duty trucks, off-road construction and mining equipment, transit and school buses, stationary generators, marine engines, logging equipment, and agricultural machinery. Multiple systems can be plumbed in series for larger applications with large sumps. The system is designed specifically for use with the AMSOIL Heavy-Duty Bypass Filter (EABP120) and is compatible with the AMSOIL oil sample valve (BK30) for convenient oil sample collection.

SERVICE LIFE
The AMSOIL Heavy-Duty Bypass Filter (EABP120) service limits are 120,000 miles, 1,800 hours, or 1 year, whichever comes first. Extended oil drain intervals should always be accompanied by oil analysis to confirm the oil remains within serviceable limits.