DEF Consumption

redwngr · January 20, 2020

On 1/9/2020 at 10:18 AM, BigWhiteMastadon said:

Finished first year on my 2019 Sierra 3500 HD, over 30,000km averaging a jug of DEF every 2700km or 11 jugs in 12 months or whatever else. Crazy. Only runs out when I leave the city limits. Usually notifies me half way through the point of no return and my destination so I can introduce myself to yet another GM dealer parts counter. It well thought out since it’s easy to over fill and spill. Like some diesel gas pumps.

One gallon jugs from the dealer or 2.5 gallon jugs?

2.5 gallon jugs with the included flex spouts that the aftermarket should mean it can be added without spilling.

(I have seen some GM 1 gallon jugs at a dealer that didn't have the spout supplied. Might be ok for a cruze -- but not for adding to the 6.6L)

What 'miles to empty' is it warning you at?

How much are you adding when you get the message.

Should get first warning at 1000 mile range. That gives the next 2 fill ups to find a station that has fuel and def. before empty.

(and even if it gets to empty, there is another 500 miles til the 65 mph / 150 kmh speed limitation)

Both my DEF trucks have run about 1100-1200 miles per gallon of DEF.

Usage depends on amount of fuel burned. Above is will averaging somewhere about 17.5 -18.5 usmpg fuel.

Only 'GM' def I've run was what the factory/dealer put in at new, and the extra 2.5 gallon jug supplied with my 18 at delivery.

The rest has been aftermarket 2.5 gallon jugs or bulk at a truckstop.

Should use about 1.5 to 2 gallons of def per 100 gallons of fuel.

So if working and getting say 10 mpg, then def usage will also nearly double from the number above.

BigWhiteMastadon · January 20, 2020

2.5 g jugs.

KM’s say 1000 to go usually.

I put in 1 or two, depending on the price where I am while on the road.

I don’t drive over 115km/hr. Too much attention in this rig.

Got a recall today concerning improperly programmed computer for DEF, in dealership right now getting it rectified. Then we will be able to see if better or worse DEF usage going forward.