Diesel Danger: Avoiding Contamination

Words by Joseph Van Woerkom

The modern common rail diesel delivers fuel at immense pressures in order to produce fuel incredibly small droplet sizes that atomise virtually instantaneously. The reason for this is to ensure that all the fuel is completely burnt, which simultaneously increases power and reduces pollution.

In order to produce these immensely high pressures, the manufacturing tolerances of the injection equipment are extremely tight which is why the quality of the fuel used is of such importance.

Any foreign matter in the fuel, be it dirt, water or organic material can cause premature wear and corrosion within the fuel pump and injectors and these can be very expensive to replace. How expensive? Well, try $1500 per injector and $3000 for a fuel pump which for a V8 diesel would amount to $15,000 if all needed to be replaced.

One of the most problematic contaminants is plain old water. This often enters the fuel system when refilling the fuel tank, especially just after a fuel delivery or when the fuel level is low in the supply tank. This is because there is invariably water in the supply tank which has got there by condensation, rain or seepage. When the supply tank is being refilled by the tanker, this water gets stirred up and it takes a while to settle down to the bottom of the tank.

Water can also condense out of the air in your vehicle’s fuel tank. This can easily happen during periods of high relative humidity when the vehicle has been driven all day and then parked for the night. The large air space in the depleted fuel tank is now heavily laden with moisture which can easily condense out as the overnight temperature falls. Refilling the fuel tank at the end of each day’s travel will help to minimise this problem by reducing the volume of moisture laden air in the tank.

My other recommendation is to ensure that your diesel vehicle is fitted with a water separation filter. These are often separate devices from the main fuel filter and their only job is to remove any water from the fuel before it gets to the main fuel filter. They usually have an electronic sensor that will trigger an alarm in the cabin when water is present in the collection bowl and a valve that can be used to empty the water.

Have you ever suffered from contaminated diesel? Drop me a line at [email protected] – I’d love to hear your story.