Common Rails and Water

Hi all

We all know that diesel engines and water do not mix. Now I have just finished reading the article in the current edition of 4WD Action that discussed the differences between direct injection diesels and common rails and the impact water in the fuel has on a diesel engine.

Interestingly they conclude that for us (common railers) using a fuel conditioner is not recommended. They highly recommend the installation of a water separator for use in common rail diesels because they do not tolerate water at all even in tiny amounts.

Later in the mag, there is a technical article on how to install a particular manufacturer's water separator into your fuel line.

So my questions are:

1) Based on previous advice (not from here) I have been using a high quality expensive diesel fuel conditioner, is anyone else doing this?

2) Do you have any views on their use?

3) Has anyone installed a water separator? If so are you happy with it?

Thnx

Gus

Bosshog said:

Has anyone installed a water separator?

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I don't have this month's mag, what's the difference between the water separator in the fuel filter, and the aftermarket one?

I have one of those aftermarket filter/water separator before the factory filter, Nearly up to 40k's now, I have never seen any water in the bowl, that includes 20k trip around Oz, getting fuel from very remote Aboriginal communities.

So IMO it's not an issue.

theres two kinds of water in diesel. theres the free water which drops out of the fuel. now this is very easily caught by filters or even just a bowl.
however its the fine water thats suspended in the fuel which is hard to get out. it can actually get through water filters. thats where you need to let the fuel settle for a long period of time (not that common as the pumps stir the hell out of the fuel tank) or use a diesel treatment which helps the water join together into a bubble which then drops out of the fuel and is easily caught in the filter.

end of the day you only need to suck up a bit of water from a poor garage once and its all over. common rail your looking at $10,000 to rebuild the injection system.
an extra filter is cheap insurance.

also if you can lengthen the amount of blockage that occurs with the main filter, the better the motor will run and less expensive filter replacements needed.
note- i've seen navaras from other countries and they come standard with dual fuel filters.

Shame there's no method of emulsifying that water in the fuel so it just gets combusted.

Pro-Nav2.7TDi said:

I don't have this month's mag, what's the difference between the water separator in the fuel filter, and the aftermarket one?

Click to expand...

Pro-Nav check out Responsive Engineering | Water Testing System | Diesel Filtration | Water Watch - Water Watch System

08KINGCAB said:

I have one of those aftermarket filter/water separator before the factory filter, Nearly up to 40k's now, I have never seen any water in the bowl, that includes 20k trip around Oz, getting fuel from very remote Aboriginal communities.

So IMO it's not an issue.

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KingCab - thats reassuring as I am off bush as soon as that water dries up from the Cooper Creek et al

tweak'e said:

theres two kinds of water in diesel. theres the free water which drops out of the fuel. now this is very easily caught by filters or even just a bowl.
however its the fine water thats suspended in the fuel which is hard to get out. it can actually get through water filters. thats where you need to let the fuel settle for a long period of time (not that common as the pumps stir the hell out of the fuel tank) or use a diesel treatment which helps the water join together into a bubble which then drops out of the fuel and is easily caught in the filter.

end of the day you only need to suck up a bit of water from a poor garage once and its all over. common rail your looking at $10,000 to rebuild the injection system.
an extra filter is cheap insurance.

also if you can lengthen the amount of blockage that occurs with the main filter, the better the motor will run and less expensive filter replacements needed.
note- i've seen navaras from other countries and they come standard with dual fuel filters.

Click to expand...

Tweak'e yes 4WD action confirmed that 5ml of water in a common rail = $10K. Think of the condensation inside a tank. Thats what led me to starting this thread.

Could you explain further what you mean by "lengthen the amount of blockage that occurs with the main filter"??

Gus

Old.Tony said:

Shame there's no method of emulsifying that water in the fuel so it just gets combusted.

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Tony, you were posting just as I was replying to the others.. I thought that was what the conditioner was meant to be doing but clearly I was badly misled.

Old.Tony said:

Shame there's no method of emulsifying that water in the fuel so it just gets combusted.

Click to expand...

there is, thats actually the problem. you don't want water to emulsify into the fuel.
common one is simply methanol. that also makes it real easy for it to get through the filters and then water does the damage.

Bosshog said:

Could you explain further what you mean by "lengthen the amount of blockage that occurs with the main filter"??

Gus

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if you trap the bigger crap in a basic pre filter it means there is less crap caught in the factory expensive filter so it wil take longer to block up.

injection pump performance is effected by the restriction caused by the filters. so if you can fit a big pre filter to stop the stock one from clogging up you should get better performance.

Bosshog said:

KingCab - thats reassuring as I am off bush as soon as that water dries up from the Cooper Creek et al

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I'm supposed to be heading up to Broken Hill, Innaminkca, Birdsville and across the Simpson late May. Hopefully the roads are all open by then.

I don't see how it can do so much damage. I'll keep watching this thread with interest.

common rails are worse because of the big increase in pressure and that everything is built to much finer tolerances. it only takes a minor bit of corrosion (you can't see it) to stuff it.

Water can't corrode parts without oxygen.
I can't see how corrosion could occur in a sealed system lubricated in oil?

water almost always has oxygen dissolved in it (how do you think fish breathe).
the injection system are not exactly sealed, tanks are still open to the air.
water can sit in lines, inside the pump or even get caught between valve seats and seals.
the worse is when the water drops out of the diesel at sits at the bottom of the pump, bottom of lines, bottom of injectors etc and the oxygen corrodes the surfaces.
water also is not a very good lube, which can allow metal faces to microscopically weld and break when they touch. this shows up as erosion.

diesel is slight hygroscopic, ie it naturally soaks up some water. diesel floats on bulk water but it does mix and hold onto very fine particles of water which are very hard to get out of diesel.

talking of air in fuel, theres more and more getting into air/fuel separators to take out the entrained air in the fuel. ie air mixes into the fuel from sloshing around in the tank.

My mechanic told me water roots CRD engines, also told me to be careful letting my missus fill it up as petrol will root it too

justdrinkbeer said:

My mechanic told me water roots CRD engines, also told me to be careful letting my missus fill it up as petrol will root it too

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You also have to watch casual employees. We had a casual put 110 litres of petrol in one of the 8 tonne trucks, didn't even take notice that he wasn't at the usual pump, just put the nozzle in and filled the tank.

and thats one of the problems. you don't know how much petrol the tanker driver has accidentally put in the diesel tanks at the servo.
even the non-CRD need good lube in the fuel. ZD30 injection pump puts out higher pressure than gen 1 common rail, thens theres the oil pressure boosted injection system, unit injectors etc. all of which will stuff up big time with water or petrol in the diesel.

you can see why so many are keen on 2 stoke oil in diesel fuel.

tweak'e said:

and thats one of the problems. you don't know how much petrol the tanker driver has accidentally put in the diesel tanks at the servo.

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Realistically I'd have to say not much, yeah sure we all make mistakes at work from time to time and you always hear horrors stories (Macca's staff spitting in burgers for people they don't like is one of the most common) but if this sort of thing happened on a regular basis there would be more wide spread problems.

There was about 12000 petrol users in Melb last year who got refinery contaminated fuel so I know problems can happen from time to time but I'd still be willing to bet that petrol in the diesel tanks anywhere there is mass storage is probably not something we all need to concern ourselves with greatly. Far more worrying to some people is what other additives are being added to the diesel.

tweak'e said:

you can see why so many are keen on 2 stoke oil in diesel fuel.

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I still don't see any valid reasons for doing it when diesel already has oil added but that's just one of those debates that will never be resolved.

I was reading a similar article to the one originally referred to in this thread and while they basically said the same thing they also talked about adding and extra filter into the system so that the vehicle had two places to stop water getting to the engine. For a cheap and easy way to help limit the water in diesel that's probably not a bad option for some people and when they do long trips it's not like a few extra filters take up much space so they can always carry 4 filters and change as often as they like.

i know from mate that worked at the local gas station (incidentally the same gas station that had water leaking into the fuel tanks) and he had one of the trucks put 10,000 litres of petrol in the diesel one night.....oops !

yeah i think dual filters is a good idea. especially as nissan does it stock standard overseas. only problem is inlet restriction which isn't good for the pumps. however a few run electric pusher pumps which over come that problem and for the complete diesel geek, in discussion at the mo on fuel coolers. a combo of pusher pump, extra filter and fuel cooler system to put some reliability back into these fuel systems.