Every 250 Hours (S660 and S670)

BM004618-UN-12FEB16

BM004693-UN-29FEB16

Fuel Filters

A - Fuel Precleaner Filter

B - Secondary Fuel Filter

C - Primary Fuel Filter

1. CAUTION: High-pressure fluid remaining in fuel lines can cause serious injury. Before disconnecting fuel lines, sensors, or any other components between the high-pressure fuel pump and nozzles on engines with High Pressure Common Rail (HPCR) fuel system, wait a minimum of 15 minutes after engine is stopped.

   Shut OFF engine, set parking brake and remove key before performing maintenance work on fuel filter.

   Fuel Precleaner Filter - Close fuel tank shutoff valve. Remove fuel precleaner filter (A) and clean screen. Install fuel precleaner filter and open fuel tank shutoff valve and allow bowl to fill (see Fuel Precleaner Filter—Cleaning in Service Engine section).

2. Secondary Fuel Filter - Close fuel tank shutoff valve. Remove and replace secondary fuel filter (B) when performance decline is noticed or diagnostic trouble code is generated. Remove fuel from filter and discard. Install replacement secondary fuel filter and open fuel tank shutoff valve (see Primary and Secondary Fuel Filter—Replacing in Service Engine section).

   Primary Fuel Filter - Close fuel tank shutoff valve. Remove and replace primary fuel filter (C) when performance decline is noticed or diagnostic trouble code is generated. Disconnect water sensor from primary fuel filter. Remove fuel from filter and discard. Install replacement primary fuel filter, open fuel tank shutoff valve, and turn key switch ON to prime fuel system (see Primary and Secondary Fuel Filter—Replacing in Service Engine section).