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water ingress in diesel

what can i buy to prevent water getting in diesel fuel on my narrowboat

Asked by: barry philpott  | 9.15pm, Saturday 21 April

WW says:

Most diesel comes in through expansion and contraction of air left in the tank, which draws in moisture from the air, which in turn lends to condensation forming, sinking to the bottom of the tank. Keeping the diesel tank as full as possible reduces this- however the risk is then that the diesel will start to decay as it has a limitied shelf life once heated and cooled, from the engine return. Ideally narrowboats would have much smaller disel tanks and a greater rate of fuel turnover!
Some water can get in through tank vents and filler caps, though this is unlikely.
First call is to regularly drain the diesel tank.
Secondly, ensure that you have a water seperator/primary fuel filter, before the engine filter, to remove any major contamination. The engine fuel filter is only designed to take out the last few drops.
You can also add pouches to the fuel tank (rather like large teabags) which can absorb excess water that you can't drain out (ASAP Supplies stock a wide range of water absorbing materials).
Finally, you can add a fuel treatment, like FuelSet to the tank, to miscify any final water, which is then carried through the filters and burnt off in the combustion with the engine.
Lastly, try and buy FAME (biodiesel) free, as biodiesel increases water absorbsion of the fuel (and more likely the dreaded diesel bug!).

Mark Langley  | 11.23PM, Saturday 21 April

And by draining the fuel tank, i Meant, draining the water from the base of the fuel tank, not all the fuel!

Mark Langley  | 11.25PM, Saturday 21 April

Marine 16 is a very good fuel treatment and shuld help reduce issues in the future- and often preferred over FuelSet- they work in slightly different ways!

Mark Langley  | 8.36PM, Monday 23 April

Readers say:

Many thanks. I have now arranged to meet a boat engineer for a full cleansing/draining of contaminates from fuel tank. He will fit a seperate water seperator/filter and will also add Marine 16 which is recommended rather than FuelSet in order to prevent further contamination of diesel. Thanks again for your advice.

barry philpott  | 8.07PM, Monday 23 April

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