Fuel System Priming

WARNING: This page is about a different car, the 2003 GMC Sierra, 2003 GMC Cab & Chassis Sierra, 2003 Chevrolet Silverado, and 2003 Chevrolet Cab & Chassis Silverado. However, it is still accessible from the selected car via links, so may be relevant.

NOTE: In order for the DURAMAX diesel engine fuel system to work properly, the fuel lines must be full of fuel and contain no air. If air gets into the fuel lines, it will be necessary to prime the fuel system to eliminate the air before operating the vehicle. Air could have entered to system in one of the following ways:

The vehicle ran out of fuel.
The filter was removed for service or replacement.
The fuel lines were removed or disconnected for servicing.
The fuel filter water drain cock was opened while the engine was running.

If one or more of the above occurred, air has entered the fuel system and you will need to prime the system prior to operating the vehicle.

Prior to priming the engine, ensure that the following is complete:

There is fuel in the fuel tank.
The fuel filter has been installed and properly tightened.
The fuel lines are properly connected.
The fuel filter is cool to the touch.
Any dirt or debris is removed from the fuel filter head and vent valve.

Open the vent valve by turning the screw counterclockwise several full turns. See Figure. Operate the priming pump until a small amount of fuel seeps from the vent valve. allow the pump to return upwards between pumps. When fuel is present, the filter is full of fuel and the system should be primed. Close the vent valve. Clean any fuel which accumulated on the fuel filter. Start the engine and allow it to idle for a few minutes. Check the filter for leaks.