So as we know, the M-B dealers tend to get about $150 to fill the Diesel Emission Fluid reservoir in our Bluetec diesels. DEF is DEF, in fact the same bottle that is sold at M-B dealers also has VW and Audi and BMW part numbers on it.

My M-B dealer sells a 1/2 gallon (2 liter) bottle for about $10, and the tank holds somewhere between 6 and 7 gallons. In fact, my dealer quoted me $10 a bottle for however many bottles it would take to fill (even though they fill from a big 55 gallon or so drum of DEF.) FYI the 7 gallons or so of DEF that the car holds lasts well more than the 10,000 miles recommended between oil changes and services.

So, I'd read that many truck stops today have a DEF pump right next to the diesel pumps for the big 18 wheel trucks. I googled and found such a truck stop about half an hour from my house. But the car's tank has a proprietary cap and you can't just stick a nozzle in there and fill it up. One person recommended buying one 1/2 gallon bottle and then cutting off the bottom, and using it as a funnel. Sounded good, so I did that....



And I learned a few things:

1. This is a two person job. You have to push down on the bottle to get it to drop the fluid into the tank, but if you push too hard and the fluid goes in too fast, then some fluid shoots up the small tube which is meant to let the air escape out of the tank while the fluid goes in. There is a delicate balance to how hard to push, otherwise you are making a huge mess.

2. The truck stop pumps don't work like gas stations that you and I are used to. You have to go inside and they activate the pump from there, and they'll look at you funny because you're not dressed like a truck driver, and your truck doesn't have a truck number. You can't just drive up and swipe your Amex card.

3. It took me a long time to pump five gallons into my car, like 20 minutes. Any faster and the DEF shoots out the exhaust tube in the bottle.

4. The only way that you know that the tank is full is when the funnel won't allow any more DEF into the tank. So you then have to unscrew the funnel, and discard the little bit that's left inside it.

5. Now the good news: My 5.061 gallons of DEF cost me $14.67 or $2.899/gallon. So I filled the tank for $15 instead of over $100.

Overall, I saved about $100. Was it worth the hassle? I'll let you decide that. For me, I am not really sure what I'll do at the end of the next 10,000 miles.

 

I think you refer to Ad Blue additive product , unless it voids your warranty there should not be a problem and in this case it's safe to say you did a good job

 

Nice report. I used the method of cutting the thread locks on the half gallon and refilling it again and again from the 2.5 Peak brand DEF bottle. Time consuming and on the last bottle the neck of the bottle where the threading connects broke but luckily noticed right away and avoided a huge mess.

I like your idea though. Do you think just cutting a smaller hole in the bottom (not much larger than the pump nozzle) will reduce the splashing from the air tube?

I know what you mean about having to waste the last amount but still wroth it I suppose.

I am not sure what I'll do next time either. My dealer estimated $50-70 I think to fill the E class, which isn't too bad.

Hopefully as time goes on there will be better solutions...

 

No need to waste anything as there is no real need to top it off completely. Just add 5 gallons and call it a day.

 

AdBlue is a brand name for DEF. As long as the DEF used conforms to the Spec Number there cannot be any warranty issues. I buy Peak DEF for about $13/2.5 gal. on sale. It conforms to the AdBlue specification. During my first 40K miles with my Bluetec, I discovered that the vehicle uses very little DEF with steady speed highway driving. Most of my DEF consumption happens in the city. I found this interesting.

 

Interesting observation. Thinking about it I think my vehicles have a similar trend. I guess it makes sense. Highway miles you burn less diesel, requires less clean up of exhaust? I would imagine there is a more direct relationship between gallons of diesel used and gallons of DEF required vs. miles drive and gallons of DEF required...

 

About 90% of my miles so far have been at a steady 65-70mph...most of the rest have been suburban.I very,very rarely drive in the city.My "add DEF" warning recently appeared at just under 18K and the "10 starts remaining" appeared a couple of hundred miles later.

 

That sounds about right. In mostly City driving, the warning would have come on at approx 10K miles. I keep my tank topped off. This "supposedly keeps the amonia from crystalizing on the walls of the tank. I would guess they dissolve when the tank gets refilled. I find that it is easy to fill, so when I am filling the winsheld washer fluid I generally fill the DEF tank at the same time.

 

The way you avoid fluid shooting through the exhaust tube is you point the tube inside the bottle (funnel). Anything that shoots out goes right back into the bottle.

 

I purchased a 1/2 gallon container and a 2 1/2 gallon container at my local VW parts department for $7.99 and 10.99 (not exactly sure but that's close). I have them in my garage...trying to figure out the best way to add fluid. My main concern is when I pour from the 2 1/2 gallon container, will it dribble down the side. There seem to be two approaches...

1) cut off the bottom of the 1/2 gal container and then pour from the big jug into the 1/2 gal container slowly (while someone is holding it down). Concern is will that big container drip.

2) try to get the fill mechanism off the 1/2 gal container so I can refill it out of the car and then connect it/push and refill the tank. Will take longer, but no spill issues unless the fill mechanism comes off in which case you have a real mess to deal with.

What seems to work the best...or is their a third approach. Heck, I could probably just siphon it in and maybe that's the best way.

Open to suggestions....that fluid is calling to me from the garage (but no indicators on the car, so I'm ok to keep driving for a while.

 

In retrospect, I would do it a little differently. In my case, I would just cut a small hole in the bottom of the half gallon jug that would barely hold the tip of the DEF pump nozzle.

In your case, I might try a thin siphon hose from the 2.5 gallon, but you'll have to go very slowly and be ready to mop up the mess when the tank is full, if you get to that point with the 2.5 gallons. There is not going to be any convenient way to pour slowly from the big jug.

 

I use the 2.5 gallon jugs from peak all the time. They have a perfectly sized extended nozzle and it is actually quite simple. if you spill around the tank, it does drain underneath the car, so there is little chance of a mess happening. All in all it is a very nicely engineered system that that is simple to maintain and keeps my diesel running cleaner than any comparable internal combustion vehicle out there.