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How Often Water/Fuel Separator Drained?

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#1 bcrocke3



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Posted 04 May 2011 - 11:29 AM

I have a question about Class A motor home on a Freightliner chassis:

Water/fuel separator: At the fuel cap area where I fill the diesel fuel, there is a sticker stating that the fuel separator should be drained after each fill up. One has to crawl up under the rear engine in order to reach and do this. I thought this to be a really uncomfortable and nasty job to have to do so often. So, I called National RV, the manufacturer (since out of business) and a person told me that this was overkill, but to still do that about every 3 or so fill ups. When the RV was new, I could definitely see that water came out for a short time, and then it would be diesel. Now, I never see water, just diesel, and have not seen anything else in last couple years. Do you think the fuel/water separator is bad or just simply not getting water in the fuel? Also, is it really necessary. I have at a couple times asked at the different RV dealers about the separator, and have yet to find one who even knows what I'm talking about, or what the solution is.

This is my first post, hope it was not too involved and long.. Thanks Bill C
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#2 wolfe10


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Posted 04 May 2011 - 11:38 AM

Checking the primary fuel filter/water separator: First a question-- do you have a clear bowl so that you can see the bottom portion of the filter or is it all metal? I MUCH prefer the clear bowl, as you can see if there is any contamination (dirt or water) without having to open the drain.

There is no real way to tell you how often to check for contamination. If all you get is clean diesel, you will never have anything in the filter but clean diesel. But, one tank of contaminated diesel-- well, you get the idea. You do not have to worry about the filter not removing the water-- that is done by gravity (water is heavier than diesel and WILL settle to the bottom of the filter. My advice is to get a clear bowl filter element and the first time you stop after filling up, look at the clear bowl. If it is clear and golden colored-- nothing else is needed. If there is any layering (water would be at the bottom, as would dirt), you need to drain until clear clean diesel comes out.
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#3 garykd


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Posted 08 May 2011 - 02:37 PM

Hi bcrocke3,
Does your fuel water separator have a plug with wires running from it? If so it may have a feature you can take advantage of. If there are wires, check to see if you have a warning light on the dash. My coach has a dash warning light that will tell me if there is water in the fuel/water separator. If the light come on, I need to do the drain exercise at the next fuel stop.
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#4 Archambeault



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Posted 30 December 2012 - 01:41 PM

I am an 0lde pilot who, as part of the preflight drained the tanks prior to each flight.
A round glass cylinder is best. We swirled the container which created a vortex and
could easily see any water or dirt particles. I try to get a funnel to catch the fuel as it
comes out as the fuel splashes on the frame picking up dirt. I would like to have a tube
attached to the drain valve and not have it splashed all over.
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#5 DickandLois


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Posted 30 December 2012 - 11:05 PM

It is a pain to check the sight bowl after every fill up and a lot of owners do not check it as frequently as we should, myself included. I do by my fuel from locations that pump large quantities of fuel and stretch out the intervals some between fill ups.

We travel in some nasty weather in the Northeast, so getting under the coach in the snow and cold is not relay on my to do list all the time.

Must admit that I have had some water in the sight bowl over the last 10 plus years though.

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