Welcome to the PM Series: PM – Change Secondary Fuel Filter

Welcome to our new “Preventative Maintenance (PM) Series” where we will discuss a typical preventive maintenance task each month.  Our goal is to communicate a PM found on most vessels by highlighting the requirements for a specific piece of equipment and then expand on equipment variations and techniques.  While you may not have the specific equipment referenced in the PM Series, the concepts should apply to your equipment.  The PM Series presents actual PMs taken from the WheelHouse Maintenance Management System.  WheelHouse users will always have the PMs and related documents and parts that are specific to their equipment.  Non WheelHouse users  should always refer to manufacturers guidance for your specific equipment when completing maintenance.  Contact WheelHouse for a product demonstration and pricing information.

PM Task – Change Secondary Filter

Change Secondary Filter


Changing the secondary (engine mounted) fuel filter is essential to the reliability of any diesel engine whether used for propulsion, electrical generation, or other applications.  The details for your generator may be different than the  Northern Lights 16kw generator in our example, so please consult your WheelHouse or Manufacturer’s Manuals  for specifics.

Most modern yacht fuel systems consist of a primary fuel filter like the Racor Turbine Filter followed by the secondary fuel filter(s) that are usually engine mounted.  Multi-stage filtration using smaller mesh filters as you proceed towards the engine eliminates the harmful particles that can damage lift pumps, injection pumps and injectors, especially in modern high pressure common rail systems.  Northern Lights, and many other engine manufacturers recommend 10 or 30 micron filters for primary filtration (not 2 micron) to provide progressive filtration without putting undue burden on the lift pump.  Your secondary fuel filter is the last line of defense in providing clean fuel to your engine and should be serviced following the maintenance intervals recommended for your engine, or more often if fuel quality is suspect.

The following general practices should be observed along with the specific details included in your engine’s owner’s manual:

  1. Turn off fuel supply
  2. Remove fuel filter and wrap in a zip-lock bag for clean and safe disposal.  Some engines may require a filter wrench.
  3. Lubricate the o-ring on the new filter and install without filling with fuel.  Adding fuel will introduce unfiltered fuel into your engine.
  4. Turn on fuel supply and fill the new filter with fuel using the lift pump in combination with the bleed nut on the filter assembly.  Specific configurations and methods for filling the filter and bleeding the system are unique to each engine.

Providing clean filtered fuel to your engine is one of the most important steps in proper maintenance of your diesel engine.

Posted in Maintenance Log.