How Much DEF Are You Using In Miles?

[kthaxton]

I used some DEF, and some fuel.

That's the most accurate data I can provide.

 

[Cummins12V98]

I used some DEF, and some fuel.

That's the most accurate data I can provide.

Honest answer!

 

[Cummins2014]

I used some DEF, and some fuel.

That's the most accurate data I can provide.

Nor do I care how much DEF I use, just don't put the miles on to track it , nor see the purpose, I guess unless its going thru it more then it should. But then again what is more then it should. Never hear much about DEF usage ,other then the old argument , pump or jug.

 

[Cummins2014]

Citing back to my 2014 3500 ownership days.....I’ll say running the DEF fluid low as I described above had no negative affects on my DEF pump.

I run it to the warning as you describe now, I just don't go thru it fast enough, I want the old stuff out before I put anymore in. And I only put in the 2.5 gal jug at a time.

I had DEF issues early on , never really knew why. Got the P207F code, which can mean bad DEF, it was checked , and was okay.

Not sure why I have had no problems the last couple years or so . Since the SCR recall, and not filling the DEF tank, its been okay so far .

 

[gsbrockman]

I run it to the warning as you describe now, I just don't go thru it fast enough, I want the old stuff out before I put anymore in. And I only put in the 2.5 gal jug at a time.

I had DEF issues early on , never really knew why. Got the P207F code, which can mean bad DEF, it was checked , and was okay.

Not sure why I have had no problems the last couple years or so . Since the SCR recall, and not filling the DEF tank, its been okay so far .

I *think* the updated programming within the SCR updates perhaps “loosened” some of the tables up a tad....those tables that may have previously set a CEL much easier.

 

[TFucili]

Nor do I care how much DEF I use, just don't put the miles on to track it , nor see the purpose, I guess unless its going thru it more then it should. But then again what is more then it should. Never hear much about DEF usage ,other then the old argument , pump or jug.

I guess I'd say I don't track my fuel and DEF because I am worried about the cost, but I figure it allows me to spot a trend if something is going awry. I'm really not OCD... no really.

 

[Cummins2014]

I *think* the updated programming within the SCR updates perhaps “loosened” some of the tables up a tad....those tables that may have previously set a CEL much easier.

Its just nice not to get those warnings, although they did turn out to be nothing.

 

[Cummins2014]

I guess I'd say I don't track my fuel and DEF because I am worried about the cost, but I figure it allows me to spot a trend if something is going awry. I'm really not OCD... no really.

I believe you

 

[slowmover]

Friends,

I'm double posting because of the TDR forum layout: I have a 4th Gen C&C truck and there is no Engine/Transmission section under 4th Gen, only 2007+ under 3rd Gen.

So that being said, I purchased my new 2017 Ram 5500 in Mar 2018 and have 10,035 miles on it. I maintain a fuel and maintenance log, but didn't think to add DEF use. I believe I'm using about a gallon every 1,000 miles. About 95% of my driving is towing 20.2KLb 5th wheel. How much DEF are you using in miles so I can gauge if I'm average, low, or high in DEF use.

Thanks for your input,

Ron

Class 8 reference:

Last three big trucks have been 579 Peterbilt with 13L Paccar engine and their 12-speed automated manual. Latest is the lightest of the three by 2k, and has slightly stiffer gearing. Vans, loads between 10-40k for the most part. USA east from IH35. Governed at 68 or 65-mph.

MPG average has been 8.3 (I set cruise these days from 62-64//mph to get traffic around me. If they aren’t, I cancel and drift down to 55 or so).

Engine idle time (this is what you boys need to track) 8.3%.

TTL miles is north of 250k

DEF use is approximately 5/gallons per 1,000-miles.

An increase in idle time percentage is directly related to an increase in DEF use.

You all need to track engine hours against the Odometer. Your Average MPH will show how you’re doing. (35-mph is the minimum for longevity).

Near or below 25-mph and I’d NEVER buy your used vehicle due to abuse. No matter how purty.

The formula:

1). Very low percent idle time
2). High Average MPH

This is also the formula for high MPG.

It’s an expensive truck. Needs a plan. Discipline. Records.

A). What’s the difference when empty or light solo load between highway and city MPG? 10%? (Higher means needs remedial driver training).

Yes it can be done. You still driving Mamas hand-me-down Honda?

B). 90% of miles are empty across a major metro?

Should have bought a car.

Make no mistake the pickup manufacturers and oil companies are laughing at you all the way to the bank. Diesel pickup power numbers haven’t needed an increase since the very first 6.7L. An overpowered truck with today’s enossions requirements are a penalty when not worked to spec. Plenty of Class 8 firms learning this the hard way.

Pickups sure as hell needed an increase in fuel economy. The tractors I drive have roughly the same rated power (or less) yet achieve MUCH better FE.

Yet I don’t see many (any) beating what my 555 does. Same drivetrain I used in oilfield pulling 22k trailers hotshot. Get there yesterday.

Record every fill. Chart engine hours against miles traveled. It will take 5k miles to get a fair average. One full year to see an accurate picture thru seasons.

Work against your old self with new habits. A plan.

Is it the rifle, or the rifleman?

.

.
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[AH64ID]

Filled up my DEF on Saturday. I'm trying to find out how much is left at 1/4, 1/2, and 3/4.

Gauge read 1/4 at fillup.

4.364 gallons of DEF at the pump, $2.959/gal (price hasn't changed at the pump since last summer), 2585 miles, 780 miles towing...rest was around town.

737 mpg DEF, 13.7 mpg diesel, 1.9% usage rate.

 

[gsbrockman]

737 mpg DEF, 13.7 mpg diesel, 1.9% usage rate.

Perhaps your truck is broken.....everything I’ve read says it should be between 2% and 3%

 

[AH64ID]

Perhaps your truck is broken.....everything I’ve read says it should be between 2% and 3%

That's the same thing I've read... oh well

 

[TFucili]

That's the same thing I've read... oh well

You must be using the high viscosity DEF...

 

[kthaxton]

You must be using the high viscosity DEF...

AMZ/OIL for sure.

 

[Cummins12V98]

I need to switch to the AMZ/OIL FULL Synthetic DEF. I averaged 500mpg towing 33k combined 10 of 25k using the regular DEF. I have been told by a "reliable" source that I will at least double my MPG with the "GOODSTUFF".

 

[HPSimpson]

I used 2% to 3% which is average for Cummins trucks this isn't rocket science.

 

[AH64ID]

You must be using the high viscosity DEF...

I haven’t tested the viscosity, but it’s Scottish Highland cow piss, so maybe that’s it.

I used 2% to 3% which is average for Cummins trucks this isn't rocket science.

That’s what they say, but in 12K miles I’m happily using less than 2%...1.7% to be exact. Can’t imagine it’s that far off of average as it’s a bone stock truck.

 

[Newsa]

I haven’t tested the viscosity, but it’s Scottish Highland cow piss, so maybe that’s it.



That’s what they say, but in 12K miles I’m happily using less than 2%...1.7% to be exact. Can’t imagine it’s that far off of average as it’s a bone stock truck.

Could be that virgin catalyst in your newish truck is working more efficiently than a 5-7 year old truck? Or maybe the DEF that came in the truck had some water evaporate out of it so it is dosing less due to higher concentratuon of DEF? (Speculation)

 

[AH64ID]

Could be that virgin catalyst in your newish truck is working more efficiently than a 5-7 year old truck? Or maybe the DEF that came in the truck had some water evaporate out of it so it is dosing less due to higher concentratuon of DEF? (Speculation)

The original DEF is long gone, and was so before I bought it. It was topped off the day I bought it.

Time will tell of usage increases with time.

 

[kthaxton]

I have no idea how much DEF I use.