What happens if you are filling the tank, it gets full, and there is still DEF in the spout connected to the tank? Seems like there is no way to get it out without spilling it all over the top of the filler. I ask because I have no idea how much is in the tank (ScanGauge says 49% for the last 2000 miles) And I don't want the level to be low during the winter when the tank heater can come on.

Last winter Scan gauge said something like 20% so I added 2.5 gallons. The Gauge went up to 98%! Now, 5500 miles later, it says 49%. Could it really only be using less than half a gallon in 1000 miles?

Can I stick a stick down the filler and get an idea of the level?

TIA...

 

Sorry, I have no experience with a DEF refill procedure (only owned gasoline powered vehicles).

One thought occurred to me - years ago, I hand-built a brake fluid feed system using a garden sprayer
(for bleeding brakes by myself).
I used an HDX pump sprayer, modifying it to apply pressure onto the brake reservoir cap ... plus it auto-magically feeds fresh brake fluid into the cap.
I've seen a video or two showing the same for a DEF fill.

I also saw another video, where the person chooses to fill DEF at a gas station that has dedicated DEF pumps - they "auto-stop" just like when you are filling the gas tank at a gas station. He obviously goes to a station that offers diesel and DEF (like a "truck stop")

I also came across this website (link at bottom), offering DEF specific pumps and auto-magic nozzles that shut off when the DEF tank is almost full.

And yes, I assume you could use a pencil-stick to manually measure the height - my guess, just slide it straight down until it hits bottom, then mark it where at the top (inside the fill neck) then measure down an inch or so to be the "fill to here" line.

Personally, I'd use a auto-shutoff nozzle connected to a supply tank (using gravity or pressure) ... or a truck -stop

https://www.fillrite.com/def-adblue/...nsfer-products

 

Thanks!

I can't believe I'm the only one asking this question! Looking through the owner's manual, it looks like you're supposed to have the oil changed regularly at the dealer, and they'll fill it then. Should you run it low, and the warning comes on, the dealer has small containers for emergencies, that are too small to over fill it.

One problem is the level readout available is not very granular, and doesn't seem to be very accurate, either, so it's hard to know for certain if there's enough room for a whole 2.5 gallon container. Last time I added 2.5 gallons it went from 20% to 98%. Since it's a 7.3 gallon tank betting I can add 2.5 gallons when it says 49% is not a good bet.

If 2.5 gallons won't fit then I'm fine since the tank is more than 2/3 full, but how to tell for sure?
[Ramblings off]

 

I just fill it until it comes pouring out of the funnel. That’s when I know it’s full.

There has to be a better way but

2015 GLK 250. 170,000 miles

 

I solved this by buying some "Mercedes" DEF from the dealership parts department. They charge about 10 bucks per half gallon if you buy a carton of four. The DEF containers have a built in valve that handles the delivery (screw in and push down) and shut off (release pressure and unscrew). So if you should happen to fill it up to the brim, you just release pressure on the container and the valve closes. There is no spillage because the valve is below the top of the tank. Any left over fluid remains in the container.

As an added bonus, if you cut the bottom of the container off (or mostly off) you now have a funnel for adding off the shelf DEF if you want. I've not tried that yet as I don't use that much before having the tank drained and flushed every couple of years. Hope this helps.






Instructions may be hard to read but it's basically take the top off, screw into DEF tank and push down.






When you push down this valve opens. O-ring prevents leakage when removing.






Now it's a funnel rather than landfill.

 

I saw this exact solution in another video (again, we only have gasoline GLK).
They bought the smaller container, and cut the bottom out to act as a huge funnel for future fills... great idea for those who need it!

 

Yeah, that's probably where I'm heading. Thanks!

 

Update:
The world continues its quest to make me feel foolish.

I purchased a 3.5 liter container of FEBI AdBlue. It has no instructions on the container or anywhere on the web that I could find, but looks very much like all the other products out there that do have instructions, like the one in post 5.


What could possibly go wrong? Well, press as I might, I could not get a drop out! I contacted FCP Euro customer service by email in the afternoon of Christmas Eve, expecting to wait until today for a response. Much to my surprise, I got a response late that afternoon. "Screw the bottle on to the tank until it bottoms then pull up (not push down) to dispense the fluid." Sure, I thought, bet it won't work. Well, sure enough, it worked perfectly...

So, Kudos to FCP Euro for responding on New Year's Eve, and for having the right answer. Points off to FEBI for being the odd man out, and supplying no instructions, especially when it seems everyone else uses "press down".

I bought two bottles in hopes that I could dissect one to figure out how to open the other one so it could be refilled. At this point, I'm thinking I'll drill a hole in the bottom big enough to take the spout from a 2.5 gallon jug, and use it as a funnel that way. Maybe I'll hack up the other one when I use it up and see, but I'm thinking there's no way to open it without destroying it.

Side note: The neck of the tank has to be all the way into the fitting on the bottle, bottomed out, if you will, to unlock the "pull up" feature. I made a "tool" from plastic pipe that allows me to unlock it, but that didn't shed any light on how to remove the valve from the bottle.