Caution: Diesel fuel containing water is still flammable. You could be burned. If you ever try to drain water from your fuel, keep sparks, flames and smoking materials away from the mixture.
Notice: If there is water in the diesel fuel and the weather is warm or humid, fungus and bacteria can grow in the fuel. They can damage the fuel system. A diesel fuel biocide can be used to sterilize the fuel system. However, the fuel system may still need to be cleaned. Your dealer/retailer can advise you of the appropriate solution.
If the fuel tank needs to be purged to remove water, see your dealer/retailer or a qualified technician. Improper purging can damage the fuel system.Sometimes, water can be pumped into your fuel tank along with your diesel fuel. This can happen if a service station doesn't regularly inspect and clean its fuel tanks, or if it gets contaminated fuel from its suppliers.
If this happens, a water-in-fuel light will come on. If it does, the water must be drained. Your dealer can show you how to do this.
If it comes on, use the following chart.
Problem | Recommended Action |
|---|---|
Light comes on intermittently. | Drain water from fuel filter. |
Light stays on at temperatures above freezing. | Drain fuel filter immediately. If no water can be drained and light stays on, see your dealer for assistance. |
Light stays on at temperatures below freezing. | Drain fuel filter immediately. If no water can be drained -- water may be frozen in water drain system. Water may be frozen in the fuel lines. Move the vehicle to a warm location to thaw out, and then drain filter system. |
Light stays on immediately after refueling, large amount of water possibly pumped into fuel tank. | Fuel tank purging required. See your dealer for assistance. |
Notice: Driving when this warning indicator is on, can damage the fuel injection system and the engine. If the indicator comes on right after a refuel, it means water was pumped into the fuel tank. Turn off the engine immediately. Then, have the water drained at once.
To drain water, do the following:
- Stop and park the vehicle in a safe place. Turn off the engine and apply the parking brake.
- Remove the fuel cap.
- Place a fuel-resistant container under the fuel filter. The filter drain valve is located on the bottom of the fuel filter. The fuel filter is located in the engine compartment on the passenger's side of the vehicle, or on the driver's side frame rail near the engine.
- Open the drain valve by turning two to three turns. When fuel empties from the valve, all the water has been drained. Close the valve hand tight.
- Remove the fuel-resistant container and properly dispose of the contaminated fuel. To find out how to properly dispose of contaminated diesel fuel, see Engine Oil for more information.
- Install the fuel cap.
- Start the engine and let it run for a few minutes. If the engine stalls, the fuel system may need to be primed. While draining the water from the fuel filter, air may enter the fuel system. If air has entered the fuel system the fuel system will need to be primed.
If the water in fuel light comes on again after driving a short distance or the engine runs rough or stalls, a large amount of water has probably been pumped into the fuel tank. The fuel tank should be purged.
Fuel Priming
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 lines to eliminate air before operating the vehicle.
Question:
How does air get into the fuel lines?
Answer:
One of the following may have happened:
| • | The vehicle ran out of fuel, or |
| • | The fuel filter was removed for servicing or replacement, or |
| • | The fuel lines were removed or disconnected for servicing, or |
| • | The fuel filter water drain valve was opened while the engine was running. |
If one or more of the above occur, it is very likely that air has entered your fuel system and that you will need to prime the fuel system before operating the vehicle. Air in the fuel lines will not harm the engine or the vehicle.
However, the engine may not be able to start until the fuel system is primed and the air is removed.
Question:
How do I prime the vehicle?
Answer:
Your vehicle is equipped with the priming pump which is part of the engine mounted fuel filter. The vent valve and the fuel filter primer pump are located on top of the fuel filter housing. The priming pump is hand operated and is designed to bring fuel to the engine to eliminate any air that may be in the fuel lines.
To prime the engine, do the following:
- Make sure there is fuel in the tank.
- Make sure the fuel filter had been installed and properly tightened.
- Make sure the fuel lines are properly connected and the fuel filter is cool enough to touch.
- Remove any dirt from the fuel filter head and vent valve by wiping with a cloth.
- Open the fuel filter vent valve by turning the screw counterclockwise several full turns.
- Repeatedly push down on the fuel filter primer pump with the palm of your hand. Let the pump return upward between pushes.
- Operate the priming pump until a small amount of fuel seeps from the vent valve. When you see the fuel, the filter is now 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 let idle for a few minutes.
- Check the filter for leaks.
