3.0 Durmax emission system problem...

Jim71 · January 7, 2020

Started my truck after work , only to see a message “service emission system , restricted to 65 mpg”. Not sure what’s up but i’ll Be having the dealership have a look this Saturday when I get the first oil change.i will be towing a car on a full trailer Thursday so great timing..

Jim71 · January 18, 2020

On 1/6/2020 at 8:47 PM, Jim71 said:

Started my truck after work , only to see a message “service emission system , restricted to 65 mpg”. Not sure what’s up but i’ll Be having the dealership have a look this Saturday when I get the first oil change.i will be towing a car on a full trailer Thursday so great timing..

Update - 3 days later the message hadn’t returned. 1st scheduled oil change tomorrow AM.Need DEF fluid as well nearly out...this 3.0 truck is fun to drive !

Matt076 · February 11, 2020

How much def do you use towing ? And what weight are you towing? I tow a snowmobile trailer that weighs app. 5000 lbs and in a trip to Michigan which is roughly 1100 miles round trip. I use between 15 and 20 gallons of fluid which seems crazy to me.

Any opinion would be great. Thanks!

redwngr · February 11, 2020

11 hours ago, Matt076 said:

How much def do you use towing ? And what weight are you towing? I tow a snowmobile trailer that weighs app. 5000 lbs and in a trip to Michigan which is roughly 1100 miles round trip. I use between 15 and 20 gallons of fluid which seems crazy to me.

Any opinion would be great. Thanks!

Something is wrong with it then.

DEF consumption on any diesel should only be a few % of the amount of fuel used.

I don't know what you fuel mpg was, but for discussion lets use 12 while towing (twice as much as daily driver use?)

1100 miles/ 12 mpg = about 92 gallons of fuel.

Instead of the 2% or less that a 6.6L dmax will use, lets use double - so 4%

4% of 92 is less than 4 gal.

Sounds like yours got 1100/15 = 73 mpg (or maybe only 55 mpg is 20 used for calc)

No way it should use 15 or 20 gallons.

That's 3 or 4 fills of the 5.3 gallon def tank!

Because of the many miles between def fills, and the low volume involved it is difficult to get an accurate reading of use.

For comparison, on my current 6.6L I verified it was full at delivery and I've tracked every drop of def added. As of last def fill it had averaged about 1100 miles per gallon, over about 25,000 miles. It tows infrequently, and hand calculated fuel fill averages are usually between 17 and 22 mpg. (it does very little 'in town' running; with all the starts and stops, it's mileage is way way worse in town/city).

Did you fill before you left and then add 15 or 20 gallons more to get it full again after the 1100 miles?

The curious want to know!

Let us know when/how it was filled and what you find out about the cause.