Either your SA is right and they haven't been filling yours properly or you have a massive leak. Using 4-5 gals of DEF in roughly 1,000 miles simply does not seem possible.

Does your paperwork show the number of gals for each DEF fill?

IMO All of us (35d owners) need to require that our dealer tell us how much DEF was used to refill the tanks. That is the only way we will be able to get a handle on the usage rates for the 35d. It pretty obvious that (at least some of) the dealers are clueless about this issue.

Funf Dreisig

Well, the invoice says they used 1 83-19-0-440-158 diesel exhaust fluid.
Also says filled both tanks. Says they checked fluid level via ISTA.

Does not state quantity of DEF used. :dunno:

Next service visit will be in about 3k for oil change. Will ask what quantity DEF they use then. It won't be long for 3k to happen. :yikes: Hope I don't need DEF filled before then. :confused: Will keep everyone updated.

That is the part number for a SINGLE 2.5 Gallon bottle.

What IS the capacity for the full refill???

They installed 6.5 gallons when they flushed and filled mine when I had my oil changed.

Craig

So why does it get flushed? I was thinking it was a consumable. Then again, my SA said oil changes took 90 minutes because of the machine that flushes the DEF.

It breaks down into separate components over time (ammonium hydroxide and carbon monoxide). It has a published shelf life of 6-12 months. That assumes it isn't stored at over 30C. When it breaks down, it doesn't work as an SCR agent any longer.

Thanks for the info. But what your SA told you and what the paper works says simply does not add up.

IIRC a single 2.5 gallon bottle will fill the small (active) tank. But it takes another 4 gals to fill the passive tank. But I can't remember which tank has the .5 gal. IOW is it 2+4.5 or 2.5+4.

I really wonder if k80jr's dealer techs understand that there are two filler receptacles -- one for each tank :confused:

Funf Dreisig

Edit:it appears that I remembered the tank sizes incorrectly. The total capacity is more like 6 gals, split between the small tank (1.6 gal) and the larger tank (4.5 gal). see my next pos tin this thread for details.

Misery loves company...

$294 Bill Shows Why Mercedes Diesels Will Piss Off U.S. Consumers - Mercedes Gl350 - Jalopnik

I'll have to check with them regarding 4 gallons in the passive tank and .5 gal in the active tank. 2 filler receptacles! This is very interesting!:popcorn: Eventually we will all(including the techs at my dealer) know how to do this!:p: Will see them soon(2800 miles til next oil change). I hope not sooner.

Not to worry, that's why each of us paid the dealer $180 in "training"....