Jim Brady

My '12 ML350 BT has 4100 mi and the ad blue fluid light came on. I was out of town and found a MB dealer and bought a case which is four bottles of 1/2 gal each about $39 total. Checked the owners manual which tells you nothing about adding the stuff nor does the manual give any technical information regarding the amount of DEF it holds.

How much DEF does it hold and how do you tell when it's full? Apparently the dealer has to reset the dash warning! Any hints from the board is appreciated.

listerone

First of all that's *not* right.There's *no* way that you should be low after 4100 miles.If it were me I'd go to the dealer and demand that the warning system be checked and,if it's OK,I'd demand that *they* fill the tank at no charge.The only possible explanations for your situation are a faulty warning system or the tank wasn't nearly full at delivery.My BT,for example,is approaching 12K miles and no warning yet.
Search both this site and "bimmerfest.com" for instructions regarding those 1/2 gallon bottles and how to convert them into useful refilling containers (took me about 10 minutes and you only have to do it once).Try searching "DEF" and you'll eventually find DIY instructions with photos.It will save you $$$ and bother. As for the procedure for filling the tank you can find videos on youtube.It's not difficult at all.In fact,it's so easy even *I* can do it!

DEF eqipped cars vary in their capacities..I think the range is from about 6 gallons to 9 gallons.Being a larger,heavier vehicle my guess is the ML would be closer to 9 but I can't swear to that.The 1/2 gallon bottles are designed to stop when the tank is full so that's not an issue,IMO.

To sum up my opinion....the dealer should address this problem at no charge.Assuming they do I'd try to return the bottles you bought (except,perhaps,for one that you'd "covert" as described above).And for future reference I don't *think* the dealer has to reset...I think the computer knows when the tank's been refilled but I can't swear to that (IIRC it varies from maker to maker).Also,in future,don't buy DEF from a Mercedes (or BMW) dealer.Way too expensive.VW dealers sell it pretty cheaply (including the special blue-topped bottles) and other places sell it cheaper still.DEF is DEF....you don't have to worry about brand names.

GregW / Oregon

Agree with listerone's comments. The BlueTEC tank holds 7.3 gallons. There have been numerouse complaints of the warning light coming on early. The capacity is designed to take you at least 15k miles on average.

Jim Brady

Thanks for the info. Back to the dealer this week for the system check.

But back to one of my questions, how do you know when the system is full?

katiesdad7

Mine came on at 5k. I got it back from the dealer yesterday and there is a software fix that corrects this problem. The software fix just came out this week. According to the owners manual a tankful should last about 13k. Since the oil is changed at 10k you are fine. AdBlue is included with the maintenance plan so you should never have to shell out cash for it.

listerone

If you're using the special blue-topped bottle (modified or unmodified) I'm 99% certain that they're desigined to stop automatically when the tank's full.Perhaps someone who's actually filled one...to the top...using that bottle can confirm or refute.I've used the bottle before but not to fill *to the top*.

listerone

I don't think it's been established that the OP has the maintenece plan.But you're surely correct that DEF ("AdBlue") is covered.

YYZ-E55

Note that the 2012 ML uses a very different filler system than the E-Class or older W/X164 where the AdBlue tank was in the spare tire well. For the 166, the AdBlue filler cap is located behind the fuel door and a regular nozzle should work fine to fill it. The dealership's bulk AdBlue system uses a nozzle that is nearly identical to a typical gas pump nozzle.

Shrdlu

Just be careful. That stuff is corrosive. If you spill any on the body paint, rinse it off quickly.

Jim Brady

Thanks Shrdlu,

Good advice. The factory MB DEF comes in a special 1/2 gal container that screws into the adblue port and should be safe to add. After I figured out how the container has to pushed to release the DEF fluid it's pretty simple. I did find some white crystals on the paint work and filler door where obviously some dripped out.

Thanks to all who contributed to my questions as it appears that there is a software fix and I suspect many dealers who maybe unaware of and may want to charge you to add the DEF like the MB dealer in San Diego did to me.

Fongletez

If you choose not to go with the dealer maintenance plan, take a road trip down an interstate and stop at a truck stop. I bought a 2.5 gallon for $13 USD and the nozzel it comes with works to fill the tank. You do NOT need the dealer liter bottle with the blue cap to fill the tank. I bought a dealer bottle just to make sure but both will work and as stated above the blue cap may stop from overfilling but i cannot confirm.

venchka

Sam's Club and Walmart sell DEF. There are lots of web pages with sources. DEF is everywhere.

Wayne

Waykool plantz

I made an appt for my 10000 mile service and wanting to avoid a high bill stopped at Advance auto parts & picked up 2x 2.5 gal Blu DEF @$13

emesap43

The AdBlue warning came on this weekend at approx 7K km. I went to the dealer today and they performed a software update and topped up my vehicle. They also updated the software related to the hesitation/bucking. All of this covered by the warranty.

axwack

I have a 2014 e350 Bluetec. Warning light came on for the DEF. I want to get one of those big jugs and replace. How should I replace this? I saw a youtube where he used one of those smaller containers with the adapter but is it possible to just use a funnel?

What's the best way to replace the DEF? Also can I use DEF and not AdBlue?

HAILERS2

Jeeez. Just get a funnel, a clean funnel and fill it up til it won't take anymore. Done. Not high tech in the least. This is like 'how do I fill up my washer reservior?' type question.

Go to Walmart and buy it by the case.

I've a 2014 with 65K on it and never had a low light come on for DEF. I get the car serviced per the manual every 10K, which in my case is way too often.

Samaral

++

jjohnsueb

Yes, it is easy as that. Locate the DEF cap, unscrew it - insert a funnel - pour in DEF until you can see fluid below the end of the funnel (pour slowly) - reinsert DEF cap - You're done. You don't need any special tubes or filler gadgets. If you are worried that you might overfill, just add a gallon every 7500 miles (or, whenever the instrument panel message tells you that the level is low). The whole procedure should take you 10 minutes - really.

Jfxogara

I buy one 2.5 gallon box at a time because that is good for 5K miles and, depending on how much you drive, the stuff goes bad over time. If it were not so easy to refill I'd probably put in two boxes.

mike919

This is a 4 year old thread friend...

rapidoxidation

11...