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Diesel fuel mileage

Discussion in 'Chevy Silverado Forum (GMC Sierra)' started by paracutin, May 3, 2013.

  1. paracutin

    paracutin New Member 100 Posts

    Looking for some real world numbers from guys that drive 2500HD's with the Duramax.
    What kind of mileage do you get? City - Highway - Loaded -Unloaded
    I am trying to justify the added expense of the diesel. I definitely do not need the added pulling power but I WANT it really bad!
    Please no replies like "my buddies dad says..." or "we took one on a trip once..." I am looking for numbers from guys that own or have owned one long enough to know the mpg under varying conditions.
    Thanks!
  2. j cat

    j cat Active Member 1000 Posts 100 Posts

    a 6 L 2500 gas silverado ext cab gets 15mpg unloaded MAX mpg. this is with 87 octane . since your on diesel you should get 19 MPG for you to get your cost factor to work......

    87 octane 335/gal diesel 400/gallon.

    so how bad is your MPG. I stayed away from these engines because it is a very expensive engine to maintain . filters/oil changes fuel .
  3. paracutin

    paracutin New Member 100 Posts

    I average 11.5 city and 14 highway unloaded on 87 octane with mud tires. When I had AT tires I got about 1 mpg more than I do now. I have tried 89 and 92 octane fuels but they make zero difference. When pulling my Pontoon (approx 5200lb) I average 7.5-8 mpg. That's on two lane highways and thru a bunch of small towns.
  4. j cat

    j cat Active Member 1000 Posts 100 Posts

    I have read reviews of diesel owners GM trucks on MPG . the MPG is between 12-20 MPG ..on the older type vehicles pre 2007. many use these in a work/haul so this explains the wide range. hopefully some one can give so input that has one and the amount of MPG with tow/haul and no load factors.
  5. tbplus10

    tbplus10 Super Moderator Staff Member Platinum Contributor 1000 Posts 100 Posts

    Until about three years ago my wife and I owned a small hotshot delivery service that operated twelve diesel trucks, we had a mix of three quarter and one ton trucks.
    Most of the trucks averaged fifteen mpg loaded and seventeen empty.
    There were two oddballs in the group, one avg thirteen loaded or unloaded and another was fifteen loaded and nineteen unloaded. Never figured out why those two trucks we were able to get were different as they were all outfitted the same and had roughly the same mileage.
    We used diesel trucks not so much for weight ratings but more for the fact these trucks acrued a lot of mileage, purchase costs were higher, but routine maintenance overall expenses were cheaper. Individual maintenance was more expensive but since we avg more miles btwn maintenance it came out cheaper over time. But something noteable is the fact gas engine maintenance periods are now increased. The big savings was overall mileage we averaged between rebuilds. If you plan on keeping and driving the truck a long time the added purchase expense can pay off, but if you typically have lower mileage and get rid of a truck within three to four years you wont see a real value with this purchase.
  6. steved

    steved Former Member 100 Posts


    The differences in mileage is likely from one or more factors...the tires and the fact that these newer engines are electronically controlled.

    Just swapping tires on my old truck would net me nearly a 3mpg gain/loss (Pirelli STRa summer vs Bridgestone Revo 2 winter).

    Further the electronic controlled engines use a multitude of sensors to make the system work, and these sensors have a range they are allowed to work without setting a MIL...get a truck that one/some/all the sensors are on the optimum side of the range and you see great mileage and/or performance, get one that one/some/all of the sensors are on the low side of the range and you see poor mileage and/or performance. I come from a long time of owning Cummins powered Dodges...as the Cummins evolved to meet EPA requirements (similar to that of the Duramax), the old 12-valves had great mileage/reliability and were consistent between trucks, the introduction of the 24-valve (with more electronic control) in 99 saw a decrease in mileage/reliability and a widening in the mileage between trucks, the introduction of the all-electronic common rail in 2003 saw a much wider swing in mileage between trucks...I'm sure the long time Duramax owners could see the same. In my last truck (2004.5 Cummins), I got better mileage towing 10k pounds than the mileages some other owners got running empty.

    Not to be a jerk, but OP, you have already made up your mind...you want one, you don't need it. There is no justification in owning a diesel...having put over a million miles on the Cummins' I've owned; I can tell you there is really no cost savings in owning a diesel (overall maintenance is more $, fuel is more $, etc.)...you pay more up front, you only get some of that back at trade. If you want one, buy one...don't try to make the $$ work, because it doesn't (again, this is coming from someone that has owned a lot of diesels).
  7. UpHighNotLow

    UpHighNotLow New Member

    Last edited by a moderator: Aug 20, 2014 at 6:07 PM

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