How Many Fuel Filters on a 6.7 Cummins and How to Change Them?

The 6.7L Cummins turbodiesel engine, equipping Ram trucks, is known for its reliability and towing capacity. A veteran within the diesel engine community, the 6.7 Cummins is especially well-regarded for its fuel efficiency, a claim that is only attainable from its impeccable, hassle-free fuel system. Within these intricate high-pressure common rail fuel injection systems, fuel filters serve a vital role. In this article, fuel filters for the 6.7 Cummins engine will be discussed, with a focus on the most pertinent concerns, such as quantity, replacement frequency, and comprehensive replacement instructions.

How Many Fuel Filters on a 6.7 Cummins?

Most 6.7 Cummins diesel engines, especially those in the Ram trucks manufactured from 2013, have two fuel filters:  

Primary Fuel Filter: Located on the driver’s side frame rail by the fuel tank. It scrubs large chunks, water, and fuel debris in the diesel before it gets to the lift pump.  

Secondary Fuel Filter: Found on the top of the engine, close to the intake manifold. It captures finer particles and fuel contaminants before the high pressure fuel pump and injectors.  

Filtering systems are arranged in this manner to provide successive level of protection. The first capture large particles, while the second guarantees the fuel is ultra clean before it gets to the diesel injectors, which is critical because the modern high pressure common rail systems are very sensitive to contamination.

How Often to Change Fuel Filters on a 6.7 Cummins?

The recommended service interval does not hinge on a singular figure and instead depends on various considerations:

1. Manufacturer Recommendation: RAM/Dodge usually prescribes changing both fuel filters at 15,000 mile intervals, given normal operating conditions. Always refer your year’s manual for the recommended interval.
2. Severe Service Intervals: Should you operate your truck under demanding conditions, reduce the interval to 7,500 – 10,000 miles. “Severe service” encompasses:
   • Regular Short Trip Usage: Engines not reaching full operating temperature for prolonged periods.
   • Extensive Idling.
   • Heavy Load Towing.
   • Operating in dusty, sandy, or dirty extremem weather conditions.
   • Biodiesel Blend Usage: Especially blends above B20.
   • Fuel Quality Problems: Lingering below standard fuel.
3. Immediate Change Symptoms: Mileage does not matter if the following is observed:
   • Regular Short Trip Usage: Engines not reaching full operating temperature for prolonged periods.
   • Extensive Idling.
   • Heavy Load Towing.
   • Operating in dusty, sandy, or dirty extremem weather conditions.
   • Biodiesel Blend Usage: Especially blends above B20.
   • Fuel Quality Problems: Lingering below standard fuel.

How to Change Fuel Filters on a 6.7 Cummins?

Replacing 6.7 Cummins fuel filters is a project within reach of a DIY owner with some mechanical expertise. The following is a step-by-step summary guide. Some details will vary slightly by model year.

Tools and Materials Required:

• New fuel filter kit (frame-mounted and engine-mounted)
• Catch pan or container
• Socket set (in this example, a 28mm or a 1 1/8-inch socket for the caps on the filters)
• Ratchet and extensions
• Screwdriver (for the frame-mounted filter drain)
• Clean diesel fuel for pre-filling
• Lint-free rags or shop towels
• Safety glasses and gloves

Step 1: Replace the Frame-Mounted Fuel/Water Separator

• Locate the Filter: The filter is located on the driver’s side frame rail.
• Drain the Housing: Put a catch pan under the filter housing. Open the yellow drain valve at the bottom of the housing to drain out the diesel fuel.
• Disconnect the WIF Sensor: Carefully disconnect the wiring harness of the Water-in-Fuel sensor.
• Remove the Housing: Using your ratchet and socket, unbolt the plastic housing from the filter head. Be prepared for some spilled residual fuel.
• Install a new Filter Element: Remove the old filter element from the housing and get rid of it. Clean out the interior of the housing with a clean rag.
• Install the New O-ring and Filter: Grease the new O-ring with neat diesel fuel and mount it onto the housing. Mount the new filter element in the housing.
• Reinstall the Housing: Mount the housing back over the filter head and fasten to the manufacturer’s torque specification. Avoid over-tightening.
• Reconnect WIF Sensor and Close Drain: Reconnect the WIF sensor and close the yellow drain valve.

Step 2: Replace the Engine-Mounted Secondary Fuel Filter

• Locate the Filter: This filter is located on the driver’s side of the engine.
• Drain Housing: Place rags around the filter housing to catch spills. Open the bottom drain of the filter canister to drain fuel.
• Remove the Cap: Loose the top cap of the filter canister with the 28mm or 1 1/8-inch socket.
• Remove the Old Filter: Just pull the old filter straight up and out of the canister.
• Install the New Filter and O-ring: Remove the old O-ring from the cap and put on the new one, greasing it with clean diesel fuel. Put the new filter in the canister, ensuring it’s seated.
• Install the Cap: Install the cap and torque it to specification. Turn the drain valve closed.

Step 3: Prime the Fuel System

This step prevents the engine from crank-ing too long and ruining the injection pump.

• Cycle the Ignition: Turn the ignition key to the “On” position (no engine running) for 20-30 seconds. You should hear the electric lift pump running.
• Repeat: Turn off the ignition, and back on to the “On” position again for a further 20-30 seconds. Repeat this process 3-4 times. This will force fuel through the new filters and remove any air from the system.
• Start the Engine: With the priming complete, the engine should now start up without issues. Drive it for a few minutes and check for any leaks around both filter housings.
• Reset the Maintenance Light: If your truck shows a “Filter Service” warning, check your owner’s manual for how to reset it.

Choosing the Right Fuel Filters for Your 6.7 Cummins

Given the importance of fuel filters, choosing the right product is crucial. The following is a list of leading manufacturers in the industry:

Fleetguard: This is the filtration brand of Cummins itself. Fleetguard filters are the original equipment manufacturer (OEM) choice and are highly recommended. They are engineered specifically for the 6.7L engine’s requirements. A key advantage of modern Fleetguard filters is their proprietary NanoNet® filtration media. This advanced, multi-layered synthetic media is designed to capture and retain a higher percentage of smaller, more damaging particles (down to 3-5 microns) compared to traditional cellulose media. This superior filtration  protects your high-pressure common rail system.

Mopar: As the official parts brand for Ram trucks, Mopar filters are another excellent choice that meets OEM specifications. In many cases, Fleetguard manufactures the filters that are then branded and sold as Mopar.  

Baldwin: Baldwin is a well-respected name in the heavy-duty filtration industry, known for producing high-quality and reliable filters that meet or exceed OEM standards.

Maintenance Tips for Longer Fuel System Life

Keeping your 6.7 Cummins fuel system in peak condition goes beyond changing filters. Follow these extra tips:

• Use High-Quality Diesel – Poor fuel quality is the leading cause of injector and pump failures.
• Drain Water Separators Regularly – Water is highly destructive to fuel systems.
• Follow the Service Interval – Don’t push beyond the recommended mileage for filter changes.
• Keep Your Tank Full in Winter – This reduces condensation and prevents fuel gelling.
• Inspect Fuel Lines – Check for cracks, leaks, or loose fittings.

Conclusion

The dual-filter system on the 6.7L Cummins is an engine protection mechanism tailored to shield your truck’s most crucial, costly, and sensitive component. Engine protection starts with understanding the system’s function, using the recommended 15,000-mile/12-month service interval, employing high-quality filters from Fleetguard, and following the guide in this manual. These simple steps will enable any owner to this vital maintenance to ensure the Cummins engine continues to provide dependable power for many more miles and years.