NCV3 DEF add rates

Curious what amount of DEH fluid y'all are going thru. We just completed a 4500 mi.
trip and used ~3 1/2 gal. That's 1 gal every ~1300 mi. Not bad, I can live with that.
Every other tank I'd add about 1/2 a gal keeping 'er topped up. Figure that's better
than waiting for a "light" to come on. Thx.

Wondering why everyone is keeping track of this?? So many threads on DEF usage...I guess I was a bit curious when I first got my van but now
I just keep topped off and run it...

Now the topping off crew vs the waiting for fill up warning group...that is the thread you want to read

After about 5000 kms.(3000 miles) I try and add a 2 1/2 gal jug of DEF usually most of it fits in the tank.

On my new to me sprinter, the top to the def tank is really screwed on tight. Is this normal, and does it require a wrench to remove?

XLent, very often residual DEF will crystallize in the threaded area of the cap and fill port... Yes, it's supposed to fit tightly, but if you carefully wipe the fill port off each time and rinse out the cap with water (don't get plain water into the tank), that should help. Kinda like the toothpaste cap that gets really hard to remove after a few months of use...

My NCV3 V6 seems to go through a gallon of DEF every 1300-1700 miles, depending on load. I'm in the "keep it topped off" camp, especially if it's going to be parked for a while.

After 17k miles I consistently average 1,400 mpg (DEF).
I fill it every 2,500 miles, easy number to remember and all internals stay “wetted”.

irvingj said:

XLent, very often residual DEF will crystallize in the threaded area of the cap and fill port... Yes, it's supposed to fit tightly, but if you carefully wipe the fill port off each time and rinse out the cap with water (don't get plain water into the tank), that should help. Kinda like the toothpaste cap that gets really hard to remove after a few months of use...

My NCV3 V6 seems to go through a gallon of DEF every 1300-1700 miles, depending on load. I'm in the "keep it topped off" camp, especially if it's going to be parked for a while.

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Thanks for the post. As a geezer, I have sort of learned to ask before "farmer tight" prompts me get the 4 foot long pipe "cheater" and the 36" pipe wrench!

I think that you folks have provided sound advice, and that I will be a "keep it topped off" believer.

What brand of DEF and where do y'all buy it? Thanks.

Generally, I buy "Blue DEF" in 1-gallon containers, available at most big box stores, truck stops and gas station/convenience stores.

Occasionally I'll get the 2.5-gallon box, but I find those very poorly designed and awkward to use -- the flexible plastic spout they come with is very likely to pop off at the worst time! I transfer fluid from the larger containers into a 1-gallon container with a good, tight screw-on cap and carry a small funnel, kept in a zip-lock bag, just for DEF (which I rinse after every use). Works a lot better than that $#@# flimsy detachable spout on the larger containers.

...And don't forget to thoroughly rinse off any spills; that stuff can do nasty things to anything metal it lands on.

As far as "tightness," I believe there are both an internal o-ring and a mechanical stop on the DEF tank fill port's cap, rather like a radiator cap. I screw it on until I feel a firm stop and then leave it alone. One geezer to another...

I buy DEF at a truck stop pump when I get the warning message on the dash.

With about 40k miles on the van, I'm getting approximately 2,200 miles per gallon of DEF.

co-kid said:

I buy DEF at a truck stop pump when I get the warning message on the dash.

With about 40k miles on the van, I'm getting approximately 2,200 miles per gallon of DEF.

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Also a vote for truck stop bulk def pumps...

Not much data from me - only a single DEF refill yielding about 1200 MPG.

I agree with the previous comments on the 2+ gallon containers of DEF. It was very awkward to use. I'm not short (about 6 feet tall) and had to use a step stool to refill from that big box comfortably. My new plan is to buy 2 of the 1/2 gallon containers from my local MB dealer. Those have a positive attachment to the fill neck and won't (ok - shouldn't) leak or drip while filling. I'll then refill those official MB containers with DEF in the big containers from my local auto parts store. I can let one drain in while refilling the other, and repeat as needed.

^ That is what I did. There is a locking ring on the cap which you can cut off using a serrated knife. Just hold the knife steady while rolling the empty bottle for cutting.

I am using a gallon every 2300 miles. I like the 2 1/2 gallon containers. I bought Peak blue at home depot for 12 dollars a 2 1/2 box. I start thinking of topping off after about 5000 miles .This vehicle is driven mostly at highway speed. Minimum of 30 miles.

2011 170" 3.0D repurposed cargo van.