Draining water from fuel filter/separator - Info?

[mystic330]

I have searched and only find a handful of topics on this subject.... Need some definitive info posted from the experienced please.

"Draining water" from the "separator" should be done every 10k according to the book. From the very few posts/videos I can find, there is a petcock (valve) to the rear of the fuel filter that you turn to release fuel/water without removing the filter.
This "Draining water" seems to me to just be draining fuel ? When you turn the petcock, you are not just getting water, correct? Water is heavier that oil, so it would make sense that water will be at the bottom of what is drained, but the "separator" doesn't seem to me to be separating anything - Are we just draining a filter's-worth of fuel which will happen to have water in the bottom? - Because it's the lowest point in the fuel system ?

From the video I watched, there is NO WAY to tell when the fuel is "running clean" coming out of the filter housing - Do we just drain until no more comes out ? That would be the entire filter, correct ?

Thanks for any detailed info you can contribute - There is very little info on this topic.

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[Synctheship]

About 45 seconds in on this video explains the process. -

Text version as well - https://www.jewrangler.com/jeep_wra...ter_separator_filter_v_diesel_engine-623.html

Here's a (long) - 9 min video of someone doing it

Around 7:30 he shows what water in the diesel will look like.


On-road diesel typically has a green/yellow tint. If you aren't sure what water in diesel looks like you can drain the whole filter (it isn't much) and then just reprime the fuel system.

 

[Jefe1018]

@Synctheship pretty much said it all. About 10,000 miles is when you should consider changing the filter all together. It is expensive, but cheaper than the headaches of letting it go too long.

 

[Free2roam]

About 45 seconds in on this video explains the process. -

Text version as well - https://www.jewrangler.com/jeep_wra...ter_separator_filter_v_diesel_engine-623.html

Here's a (long) - 9 min video of someone doing it

Around 7:30 he shows what water in the diesel will look like.


On-road diesel typically has a green/yellow tint. If you aren't sure what water in diesel looks like you can drain the whole filter (it isn't much) and then just reprime the fuel system.

How do you reprime the fuel system?

 

[Synctheship]

How do you reprime the fuel system?

around 9min22s


WITHOUT your foot on the brake press the ignition 2 times so that is in the RUN position/light. The fuel pump should run for about 30 seconds without trying to start the vehicle. Press ignition again to OFF mode.

Do this 2-3 times or however many more until you are comfortable. You can't "Overprime" the system.

https://www.jewrangler.com/jeep_wra..._has_run_out_of_fuel_v_diesel_engine-625.html

 

[Vtur]

I've had drained twice without any trace of water in mine.

 

[mystic330]

Yep - I’ve watched both of those before… and read the book, and read the limited posts.
TBH I can't tell any difference with color in his water bottle...

So there is no "separator" and best practice would be to open the drain until no more fuel comes out (filter is empty)? And then prime the pump by turning on the ignition (not starting) several times before starting?

 

[Rusty PW]

Yep - I’ve watched both of those before… and read the book, and read the limited posts.
TBH I can't tell any difference with color in his water bottle...

So there is no "separator" and best practice would be to open the drain until no more fuel comes out (filter is empty)? And then prime the pump by turning on the ignition (not starting) several times before starting?

If you can't tell if there is water in the fuel. Then you have no water to begin with. If you put what you drained out in a bottle and let it set for a few minutes. If any water is in the fuel. It would settle to the bottom of the bottle.

There is no water separator in the fuel system. You are correct in draining the fuel filter. Then repriming the fuel system with the push button.

 

[mystic330]

Ok - thanks (we’re getting more accurate information)

So as for step 1 - I assuming the “within 10mins of vehicle shutdown” is important - because I just turned the valve about 3 turns and NOTHING … (don’t want to go any further - does the valve (which I’m now calling a threaded plug) unscrew completely?)
I’m assuming because there is no pressure in the fuel system (it’s been sitting all night) there is nothing coming out.
Gonna fire it up and try again.

 

[mystic330]

Nope…. Still nothing after running it, shutdown, and immediately turning the valve…..

 

[Synctheship]

do a few turns on the valve so that some threads are showing. You don't need to take it all the way out. You can see the threads of the plug/valve in the video above.

 

[mystic330]

Thanks - Yep - I unscrewed it several more times and got a drip, another 1/2 turn and it was flowing ? - probably 5-6 full turns all together…
It’s very unnerving as the plug gets really loose - very much like an oil drain plug - and I don’t know if it completely comes out…
I got to probably the ~12oz mark and couldn’t see any diff, so I stopped.

I’m not sure if the running it did anything or not as I don’t think I turned it enough anyway the first time - the book says to drain it within 10mins of shutdown, so I’m assuming they want some pressure in there…

 

[mrmo]

You have to take the plug almost to the point of it coming out. The several times I have done this, one of the first times I went too far and it came right out and diesel all over the place including me. Its a piss poor set up. Cheaply made.

 

[Sandevino]

Poor design and half assed instructions. Crack the drain once every 10k miles and if green diesel comes out there’s no water in the system. Key on a few times without starting to prime the air out and off you go.

 

[mystic330]

You have to take the plug almost to the point of it coming out. The several times I have done this, one of the first times I went too far and it came right out and diesel all over the place including me. Its a piss poor set up. Cheaply made.

Yeah - That was my fear - Thanks for confirming that it does indeed come all the way out.
So turn it until you get fuel out of the drain and then stop turning!

Next up will be to change the filter - Then I'll get a good look at the poor design of the cap.

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