Draining Fuel From Water/Fuel Separator (Diesel)

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WARNING: Diesel fuel system may be contaminated with fungi or other microorganisms. Keep contaminated fuel away from open skin cuts or sores to prevent skin irritation or infection.

WARNING: DO NOT drain fuel/water separator when engine is running or hot. Allow engine to cool before draining. Verify that the WATER IN FUEL light on instrument panel is OFF.

Turn off engine and block drive wheels.
Remove fuel filler cap(s) to release any pressure or vacuum in the vehicle fuel tank(s).
Place a suitable container under the filter drain hose.
Open the drain valve. See Fig 1.
Start engine and allow to idle for 1 to 2 minutes or until clear fuel is observed.
Close the drain valve and stop the engine.
Replace fuel filler cap(s).
Dispose of drained mixture in a proper manner.

Fig 1: Fuel Filter Drain Valve (Diesel)

Courtesy of GENERAL MOTORS CORP.

NOTE: For more information regarding Diesel Idle Speed Adjustments refer to the ADJUSTMENTS - 6.5L DIESEL article in the ENGINE PERFORMANCE section.