Been out of town for a couple of weeks, so just got around to disassembling my water separator today to further investigate the filter element. A bit of a bear to get apart, but sticking the assembly in a vise while turning the threaded ring nut with a strap wrench eventually did the trick. Anyway, I'm very confused as to how this thing is supposed to work. Looks like diesel enters through the top and goes down thru the middle of the filter element. Is that mesh screen fine enough to only allow water through and not diesel? Meaning the water would then fall down into the canister and collect there. If so, I'm confused about the location of the exit line that takes fuel to the engine, as this appears to be sucking from the outer side of the filter element, which would seem to me to expose any water in the canister to being sucked into the engine. What am I missing?
Water separator question
- Thread starter glennm01
- Start date
gait
Explorer
the filter just filters out any large particles, the bowl is part of water separator.
the flow is sufficiently slow that any water sinks to the bottom of the clear bowl, the diesel floats and is drawn through the exit to the engine fuel pump.
inspect bowl every so often and, while engine off, release the valve at the bottom to drain out water, before there's so much water its sucked to the engine.
it may also be there's a bit of a swirl in the bowl so the heavier water is sent to the edge of the bowl before sinking, but I haven't looked that closely.
the flow is sufficiently slow that any water sinks to the bottom of the clear bowl, the diesel floats and is drawn through the exit to the engine fuel pump.
inspect bowl every so often and, while engine off, release the valve at the bottom to drain out water, before there's so much water its sucked to the engine.
it may also be there's a bit of a swirl in the bowl so the heavier water is sent to the edge of the bowl before sinking, but I haven't looked that closely.
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So there should be no diesel in the clear bowl itself, right? When the engine is shut off, what's to stop any fuel that hasn't reached the pump yet from draining back into the canister then? Is there a one way valve on the line going from the separator to the fuel pump so that can't happen? I ask because my canister is filling up almost immediately...as I think I previously said, simply starting up the engine (with an empty canister), driving across the yard, and shutting her down...the bowl will have easily a couple of inches in it, and it seems to be mostly/all diesel.
PKDreamers
Adventurer
Hi the canister bowl should always be full when then the engine is stopped or running.
Really? That's excellent news if so, but then, how do you know when it's time to open the drain plug to let any water out? Will it be visibly clear that there's an abundance of water settled on the bottom of the tank? Sorry if I'm being a bonehead and overthinking this. It's my first diesel vehicle. Much to learn...
Aha. So I guess nothing's wrong after all. I had assumed there should only be water in that canister, so when I saw only diesel in there, I figured the filter mustn't be doing its job. So really, the filter element has nothing at all to do with separating fuel and water, and instead, it's really gravity that's doing the work.
Aussie Iron
Explorer
You got it.
There should be a little red ring in there that floats on the water but not the diesel at the separation layer to indicate water level.
Dan
Okay, one last question before I finally put this matter to rest -- can someone post a photo or at least describe how/where the separator assembly is supposed to mount to the chassis? Mine was actually just loosely resting against the frame when I bought the truck, and I can't find any existing bolt holes anywhere that match the holes on the assembly. I'm guessing that I must be missing a bracket somewhere? I can easily fabricate something, but would like to make it as close to stock as I can.
PKDreamers
Adventurer
The water separator has 2 10mm or 8mm holes in it to mount it.
Mine is a dual cab and has a right angle bracket to fit it . Not sure on how a single cab separator is fitted.
While you are there it would be a good idea to change to fuel filter too. There is a bleed bolt on top of that 14mm?? and the primer pump on the pump to bleed the system.
Mine is a dual cab and has a right angle bracket to fit it . Not sure on how a single cab separator is fitted.
While you are there it would be a good idea to change to fuel filter too. There is a bleed bolt on top of that 14mm?? and the primer pump on the pump to bleed the system.
I guess I'm missing a bracket. I found a couple of photos online that show the separator mounted just to the right of the tank, but there's nothing there on my truck that matches the holes on the separator. So I ended up mounting it to the brace that holds the air filter enclosure in place. There was already one unused hole on there that would work, so I just had to drill another one, and all is now good. Thanks everyone for all the assistance!