Donaldson DBF6776 Blue® Fuel Filter | Premium Secondary Fuel Filter for Cummins X15 & ISX Engines

Donaldson DBF6776 Blue® Secondary Fuel Filter for Cummins X15 & ISX Engines

The Donaldson DBF6776 Blue® Fuel Filter is a premium secondary fuel filter engineered to provide maximum injector protection and superior fuel cleanliness for Cummins X15 and ISX diesel engines. Built with Donaldson's advanced Synteq XP™ synthetic media technology, the DBF6776 delivers significantly cleaner fuel than conventional fuel filters, helping protect expensive fuel system components while reducing maintenance costs and downtime.

Modern common rail fuel systems operate under extremely high pressures, making fuel cleanliness more important than ever. The Donaldson Blue® DBF6776 is designed to capture and retain injector-damaging contaminants while maintaining optimal fuel flow and performance. Donaldson states its Blue® fuel filters with Synteq XP™ media can provide fuel up to four times cleaner than leading competitor filters, helping maximize injector life and engine reliability. :contentReference[oaicite:0]{index=0}

Designed specifically for severe-duty commercial trucking applications, the DBF6776 is a premium upgrade over the standard P555776 fuel filter and is trusted by owner-operators, fleets, and diesel performance shops seeking the highest level of fuel system protection available.

Key Features

• Premium Donaldson Blue® fuel filter
• Advanced Synteq XP™ synthetic filtration media
• Provides fuel up to 4x cleaner than leading competitors
• Superior injector protection
• Excellent contaminant retention under vibration
• Designed for severe-duty environments
• Helps reduce costly fuel system repairs
• Spin-on design for easy installation
• Fleet-proven Donaldson Blue® performance

Donaldson highlights that Blue® fuel filters are designed for superior contaminant capture and retention, especially in demanding heavy-duty applications where vibration can cause inferior filters to release trapped contaminants back into the fuel system.

Specifications

• Part Number: DBF6776
• Brand: Donaldson Blue®
• Filter Type: Secondary Fuel Filter
• Style: Spin-On
• Media: Synteq XP™ Synthetic Media
• Thread Size: M90 x 2 mm
• Outer Diameter: 118 mm (4.65")
• Height: 224 mm (8.82")
• Application: Cummins X15 & ISX Engines

FleetPride lists the DBF6776 as a 4.65-inch OD spin-on secondary fuel filter with M90 x 2 mm threads designed for heavy-duty diesel fuel systems. 

Benefits of Upgrading to Donaldson Blue®

• Superior injector protection
• Cleaner fuel delivery
• Reduced fuel system wear
• Improved fuel system reliability
• Extended component life
• Reduced maintenance costs
• Maximum fleet uptime
• Enhanced performance in severe-duty environments

Common Applications

• Cummins X15 Engines
• Cummins ISX Engines
• Freightliner Cascadia
• Peterbilt 579
• Peterbilt 389
• Kenworth T680
• Kenworth W990
• Kenworth W900
• International LT Series
• Western Star Trucks
• Commercial Fleet Operations

Donaldson specifically references Cummins X15 and ISX applications for the DBF6776 platform. 

Major Cross Reference Numbers

• Donaldson P555776
• Cummins 5365988
• Cummins 4331007
• Fleetguard FF1219
• Baldwin BF9885
• TruckPro DNDBF6776
• Donaldson P556776

The DBF6776 serves as the premium Donaldson Blue® upgrade for the standard P555776 fuel filter used in many Cummins fuel system applications. 

Why Premium Fuel Filtration Matters

Fuel injectors for modern Cummins X15 and ISX engines can cost thousands of dollars to replace. Even microscopic contaminants can damage injector tips, reduce fuel atomization, and negatively impact fuel economy and performance. Premium synthetic media filtration helps remove these contaminants before they reach sensitive fuel system components.

Many diesel technicians recommend premium filtration and shorter service intervals as one of the most effective ways to extend fuel system life and prevent expensive repairs. Community discussions among diesel owners frequently emphasize the importance of maintaining clean fuel and replacing fuel filters before restriction becomes excessive.