A modern diesel engine consumes only a small portion of the fuel it draws, the rest of the fuel circulates back to the tank.  Fuel water separator traps (as used by Water Watch) help in removing fuel contaminants by separating water and particles from the fuel in every cycle without any restriction to the flow of fuel through the system.  

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• A fuel-water separator has the ability to remove free, dispersed and emulsified water and particles with greater than 95% efficiency.

• Research indicates that in high pressure fuel systems typical of common rail, mechanical filtration (filters) is extremely difficult, as not all dispersed and emulsified water can be captured by even the most advanced filters, which your factory fitted filter is.

• Modern common rail systems are typically equipped with a "Water In Fuel" warning light to alert operators to the presence of free water, but those warning lights are not activated by untreated emulsified water (commonly found in motor vehicles).

• Secondary filters will cause a restriction to fuel flow in Common Rail Diesel vehicles because the filter medium is a physical barrier designed to trap particles.

• Placing a secondary filter on a vehicle is a duplication of the OEM filter already on the vehicle – which provides little protection against water damage. 

• Original Equipment Manufacturer (OEM) vehicle fuel filter is a sedimentation and coalescent type, containing a water trap, which does not cope with providing water entrapment at the high flow rates experienced in a CRD system, eg. 60 Litres/Hr. for a typical 3 Litre engine. Damage debris is continually cycled around the system.

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​Is there anything you can do to protect your diesel?

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• Yes - for WATER we recommend that you have a "Water Watch unit" fitted (its a water separator and detection system - not a filter - filters can only remove particles - Water Watch removes fluids and particles from fuel flow under pressure and at high temperatures) 

• For PETROL CONTAMINATION, we recommend you install a "Diesel Key" - to ensure that you don't accidentally fill up with petrol or worse still, Ad-Blue.   No - you can't use a high flow filler with it, but that not advisable unless you're driving a large commercial vehicle (it can be removed on occasions where needed).

• For DUST, you should extend your fuel tank breather to a place in your engine bay - especially if you are driving on dirt roads or exposed to fine dust particles.  

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