Cummins/Onan — Fuel Filter - Replacement
Maintenance · fuel system
From a Cummins/Onan owner's manual covering: 6C8.3, 6CT 8.3, 6CTA8.3. Check it applies to your exact model before use.
Applies to: Cummins/Onan 6CTA8.3, Cummins/Onan C Series, Cummins/Onan 6CT8.3 engine
Before you start
- The pressure of the fuel in the line is sufficient to penetrate the skin and cause serious bodily harm
Parts for this job
Part numbers from the service-parts list for Cummins/Onan C Series. Verify against your serial number before ordering; some links are affiliate links.
Procedure
- Clean the area around the fuel filter head.
- Remove the filters and clean the gasket surface of the filter head.
- Replace the o-ring.
- Fill the new filter(s) with clean fuel and lubricate the o-ring seal.
- Install the filter as specified by the filter manufacturer.
- Vent low pressure lines: open bleed screw and operate lift pump plunger.
- Tighten the bleed screw when fuel flowing is free of air.
- Vent high pressure lines one at a time at the injectors.
Tools required
Tool links are Amazon searches (affiliate links); manufacturer special tools may only be available from a dealer.
Specs & values
- Line fittings 25 Nm [18 ft-lb]
Full service-parts list: Cummins/Onan C Series →
Source: Cummins/Onan owner's manual. Steps and values are as documented; always cross-check against the official manual and any later revisions for your exact serial number before servicing.