Removing water from a diesel fuel system

[pitman]

Hi all,

I was wondering what fuel additive or what else you have been using to remove water from a diesel fuel system.

When the temperature reaches the freezing point in the moring, the car is shaking like a tractor some seconds, shaking faster and faster until she finally starts.

I will drain the diesel filter this night but just in case there would me more water in the tank or elsewhere I would like to add something that removes the water from the system.

Methylated spirit if you still can buy taht or something similar or some additives from the motor shop maybe if they're not too pricey.

[jonathan_dyane]

Are you sure that the problem is caused by water in fuel and not another starting problem such as bad glowplugs causing difficult starting when it's cold?

The only chemical I know which will remove water from fuel does so by allowing it to be burnt, which I would not recommend in a diesel as you really don't want water passing through the injector pump; if there is water in the diesel IMO you are best off just having a more regular scheme of draining water from the trap under the filter, or if contamination is extreme removing the sender unit from the tank, syphoning off it's contents completely and starting afresh.

[pitman]

I am quite sure. The car starts like a charm when it's 3 or 4 °C and higher and the show starts when it's about 2 °C or lower.

Why should a difference of 2 degress make fail the glow plugs or anything else before them?

Last year, this shake-the-car show started exactly at the freezing point. Now, it's about 2 degrees more. I presume it's not only water so the freezing point is 2 degrees higher.

I only forgot to check the fuel system during summer. I now got caught by surprise again and have to sort this out when it's dark and cold and rainy outside.
So, any hints for solving the problem with as less physical effort as possible are very appreciated.

[DavidRutherford]

I am quite sure. The car starts like a charm when it's 3 or 4 °C and higher and the show starts when it's about 2 °C or lower.

I'm inclined to agree with Jonathan above that water in the fuel is a bit of a red herring. I suspect you have some other issue that is making starting difficult, be it poor compression, a slightly duff injector, a bit of air in the fuel or something like that. If you had water in the fuel, you would have rough running all the time

Diesel engines are extremely susceptible to temperature changes, for example the Perkins engine in my LandRover (which has no glow-plugs and the lucas thermo-start is broken) starts perfectly at 8°C or above, struggles between 6°C and 8°C, and flatly refuses to start below 6°C.

One thing you can do to prove this: have an assistant try to start the engine when it's cold (when you know you're going to have trouble) and while cranking, poke a flame (Plumbers butane torch, blowlamp or something like that) into the intake manifold. If the engine now starts and is an improvement, you've just proven that it's an issue with compression temperatures.

[ken newbold]

Is your cold start cable thingy working properly?

[prm]

I would suspect possible injector/filter problems as previously mentioned.

You could try fuel additives, Water-out, Tank Dry, or any type that helps to remove emulsified fuel where water is held in suspension.

Would recommend having a quick look in the fuel tank, at approx ¼ capacity.
If you jack up the rear end as high as possible, then lower the suspension fully Remove the tank sender under the rear seat and uses a torch to inspect the tank.
Any signs of black/brown jelly in the base needs to be removed by vacuum, prone to restricting fuel flow in cold weather, also, it’s corrosive. An old cycle type pump works well.

This biological bacteria jelly, combined with any water present, feeds of the fuel to generate fungi. We call it’ snot!!

Regards

[pitman]

Is your cold start cable thingy working properly?

Do you mean that cable between thermostat housing and injection pump?

I haven't checked that, so far.

Thanks, lads. I got now some really good things to try when I'll start next time the car.

I'll try the blowtorch first and the idling cable, then drain the fuel filter. Then I will have a look at the tank and may use some additives.

[MULLEY]

If you have got fungus in your tank, i've got some stuff that you can pour in that removes it, if you get stuck & ever head over my way (Chesterfield ish)?

[pitman]

Thanks for that offer, Mulley.

I remember it's not that far from the M1. Normally, my horizon ends at Sheffield but when I'll go further South I'll send you a PM.

[MULLEY]

Always welcome to pop round, the stuff will be free of charge of course