DEF consumption on Isata 5

[BMW Rider]

I just added another 5 gallons of DEF to to my Isata 5. This is now 12.5 gallons in less than 5,000 miles. The Mercedes engine on my Forester used significantly less than half that over 10,000 miles. Putting DEF in this unit is one king size pain since the fill tube is so far inset from the body you have to use a long funnel to fill it. What type of DEF consumption are other 5 owners getting? Is the flow rate set at the factory and is it adjustable?

[Teich]

Originally Posted by BMW Rider

I just added another 5 gallons of DEF to to my Isata 5. This is now 12.5 gallons in less than 5,000 miles. The Mercedes engine on my Forester used significantly less than half that over 10,000 miles. Putting DEF in this unit is one king size pain since the fill tube is so far inset from the body you have to use a long funnel to fill it. What type of DEF consumption are other 5 owners getting? Is the flow rate set at the factory and is it adjustable?

I've used about a quarter of the Def tank in my first 900 miles

[DavidMort]

I have not been keeping close track but on our current trip I have put in 5 gallons of DEF for about 2300 miles. Think I started almost full and now at 2/3 full with the 5 gallons in.

By the way I use the blue DEF from Walmart. If you stretch the tube that comes with it as far as you can before you put it on the container it will reach into the fill tube without a funnel. You have to hold the container up close to the RV to fill.

[BMW Rider]

Based on these comments it looks like I'm in about the same range as others. I found a tube on Amazon that fits on the containers from Walmart, is about 2 inches longer than the spout that comes with the DEF and has a turn off turn on capability. Works very well but still a pain. Thanks for the input.

[halla]

No comment on consumption because we have a different Dynamax. But I bought 55 gallons last year, much cheaper than 2.5 gallons at a time.

[Luv70sFords]

Master diesel technician here. To answer some of your questions, no the DEF flow is not adjustable, it is metered in response to output of NOX gasses from your engine. You are probably using more due to your other reference vehicle being older. Engines are utilyzing DEF more now for NOX gas emissions and relying less on EGR. This is a good thing, because EGR loads your engine up with carbon, which drastically reduces engine life. Eventually I hope to see EGR go away completely and rely on DEF because it is actually a much better system. Better fuel mileage, less soot so less regeneration cycles of the DPF, etc.

If you have any specific questions, let me know.

[Kenny kustom]

Originally Posted by Luv70sFords

Master diesel technician here. To answer some of your questions, no the DEF flow is not adjustable, it is metered in response to output of NOX gasses from your engine. You are probably using more due to your other reference vehicle being older. Engines are utilyzing DEF more now for NOX gas emissions and relying less on EGR. This is a good thing, because EGR loads your engine up with carbon, which drastically reduces engine life. Eventually I hope to see EGR go away completely and rely on DEF because it is actually a much better system. Better fuel mileage, less soot so less regeneration cycles of the DPF, etc.



If you have any specific questions, let me know.

My opinion of def differs from yours.
Most likely due to -50 temperatures which def doesn't like.
Every single def equipped vehicle I have owned, has had almost the entire system replaced.

[D. J. Schuler]

Something new to talk about around the camp fire, gotta love diesel.

[Jim34RL]

Originally Posted by D. J. Schuler

Something new to talk about around the camp fire, gotta love diesel.

No, its the EPA that has caused this mess and the use of DEF. Diesel engines are great engines from the early 1920's to 2010. After 2010 the Tier IV BIN 5 rules took effect. The Cummins engine ran exceptionally will in pick-up trucks from 1989 to 2006 and would easily pass the 500,000 mile life expectance.

[FOURWHL]

I'd also keep in mind the bigger engines use way more DEF than the smaller ones. If you went up in engine size that could be why. The 8.9L in my DX3 uses 1gal/50gal diesel pretty religiously so I'm through a 5 gal tank in about 1000 mi. My audi 3.5L gets topped off at oil changes, I've never put any in (but that could be just because they're not actually using it ... insert dieselgate joke here)

[bclemens]

Freightliner tells us average consumption..I thought it was 1/4 gallon per 100 miles, but I can never remember. It might have been one gallon per tank...which seems more in line with what you are seeing. 2 gallons of DEF for a full refill.

[BMW Rider]

I have the isata 5 so I'm on the Dodge Ram chassis but it think I'm getting about 400 miles on a gallon so the consumption is close to the same. I was towing an extra 3,800 pounds with my Wrangler.