How to Drain the Fuel Coalescer

How to Drain the Fuel Coalescer - Gen 5 DD15 - Ops - #7628

Incorporated into the fuel filter module is a coalescer. The coalescer removes water and/or sediment and is located in the lower portion of the fuel filter module (see graphic below). Water in fuel can seriously affect engine performance and may cause engine damage. A water-in-fuel (WIF) dash indicator will warn the driver when trapped water needs to be drained.

  1. Final Fuel Filter Cap
  2. Pre Filter Cap
  3. Water Drain Valve

Fig. 1, Fuel Filter Module

  1. Place a catch pan under the fuel coalescer to collect any water/fuel or sediment drained from the fuel coalescer.
  2. Open the water drain valve (3) located under the fuel filter module (see above graphic). Collect and dispose of water/fuel or sediment drained from the fuel coalescer in an environmentally responsible manner, according to state and/or federal recommendations.
  3. Allow the water/fuel or sediment to drain.
  4. Close the water drain valve (3) (see above graphic). Do not over-tighten the water drain valve. Failure to properly tighten the water drain valve may cause damage to the water drain valve and housing.
  5. Prime the fuel system with the built-in hand primer (about 50 strokes). The hand primer should not be used to prime any other type of fuel system service, as it will not provide sufficient priming, which may cause damage to the high pressure fuel pump.
Note:
Document Number: 0000009709
Manual Publication Date: 2024-01-03
Topic Publication Date: 2023-12-10