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Chevy Silverado and GMC Sierra Duramax Fuel Mileage



  • valdezvipvaldezvip Posts: 2
    Anybody have fuel numbers on the 360hp duramax.
  • bcheepbcheep Posts: 1
    Just got one in April 06. Started out low 14's and now it is climbing. 15.2 yesterday. A friend has one and he is 18-19 but has 20K miles. Peeps tell me they get better as they get broked in, and they dont get broke in until 20k or so.
  • valdezvipvaldezvip Posts: 2
    Thanks bcheep. How do you like the hp on the new duramax? Does the extra 50hp make a big difference. I just test drove one yesterday and I was really impressed. I am sure the 6 speed allison helps alot too.
  • gemini5362gemini5362 Posts: 17
    I watched a mythbuster episode where they tried different fuel additives. Although they tried them in a gasoline powered car one of the ones that they tried (adding acetone) is supposed to increase diesel mileage also. The mythbusters episode showed where this actually decreased fuel mileage somewhat. I agree with the person that said for better fuel economy drive slower. I would expect the 2004 with the 6 speed allyson to get better mileage if you get the same engine (LLY) When I test drove one of those at 2000 rpm I was doing 75 miles an hour. With my 2005 and the allison 5 speed I am only doing 65 miles an hour.

    I looked at the label on a quart of Mobile 1 synthetic oil for trucks and suv's it showed that it was authorized for use in all turbo diesels and showed that it passed the GM standard. Since Mobile 1 came stock in my new porsche and stock in my sons BMW motorcycle I believe it probably should hold up well enough in my diesel truck
  • I have a 2006 2500 Duramax Crew long bed and am getting 17-18 MPG around town. Truck has 9,000 miles on it. A friend of mine has a '01 Duramax and he gets 20 MPG around town. I'm told MPG will improve with mileage. I sure hope so. I was considering a free flow exhaust and maybe another air filter to improve MPG. With diesel fuel prices(thieves) above regular gas, I sometimes wonder if I would have been better staying with a gas motor. I really do like the truck though, I had an '02 1500 Silverado Ext. and moved up to the diesel for towing the travel trailer.
  • rseeborseebo Posts: 12
    As in Message 207, 05 Duramax with Banks, I am now experiencing high eng. temps and trans temps.. Is it customary to see 225 engine and 220 trans in heat of 103 while towing a 6k trailer/sled? I had the air off and the incline was very minimal and was going 60 when it started to creep up. Honestly, I am almost at my wits end :mad: with GM products. I love the truck and its style, but it has been a problem since day 3. I saw Fords, I know, pulling bigger trailers with their air on and doing about 65 - 70 with no issues. Any thoughts? HELP
  • Hey I bought a new 2006 Duramax 2500HD 360 HP and made it 2 miles from the dealership and broke down. I shut the truck off and when I went to start it, it fired and then shut off and wouldn't restart. I have herad they are having some problems with fuel issues. Can anyone tell me anymore information? The truck they gave me to drive has 3900 miles on it and gets 19mpg. Thanks
  • coontie57coontie57 Posts: 128
    I guess I will be buying one tomorrow so I don't know the mileage but ???

    What happened to the truck?

    I hope I can get mine home before it quits...
  • bob129bob129 Posts: 1
    I own a 2005 Duramax with the Allison Transmission. My mileage when new was 16-19 mpg. The vehicle currently has 20,000 miles on it. For the past 6 months I have noticed the mileage being 13-16 average. From the start, I have the Edge with Additude chip. I had run it mostly on "3". . the drive mode. With the drop in mileage I have tried different settings and it doesn't appear to change much. I had the dealership check it out and they said everything tested fine. They also suggested trying to run it on "0" which means the Edge is turned off. The mileage did not increase. Has anyone else experienced this drop in mileage from when the vehicle was new? Seems like most people are getting better mileage when the engine has more mileage on it. I love the power and the truck but am very dissatisfied with the milege. Any help would be appreciated.
  • rseeborseebo Posts: 12
    I had the same issue with my Banks setup. I hadn't replaced my fuel filter until 40k, big mistake. It is to be done every 15k. Once I replaced it I went back up to 22 MPG's.
  • pescadorpescador Posts: 7
    This is the fast idle feature that is new on the 2006. It places a load on the engine when cold so that it warms up quicker. Mine does the same.
  • pescadorpescador Posts: 7
    I plan on using Amsoil synthetics in my new 2006 Duramax. Does anyone have any suggestions on how many miles to put on it before doing so to make sure proper break in has occurred? I am still averaging around 15.2 mpg and only have 2500 miles on it.
  • coontie57coontie57 Posts: 128
    I got the new Chev diesel Monday and now with 340 miles on it myself (440 total) the speedometer says I got 17.4 for the whole 6 days worth of combined mileage.. Not bad as we live in the MTNS of NC... I drove down to SC fishing Sat afternoon and back 150 round.

    I am sure on the road its going to do quite well. Now if I could just figure out how to reset the trip meters etc.
  • kd7caokd7cao Posts: 3
    Sorry about the slightly off topic post:

    I am looking at purchasing either the GMC Sierra 3500 4x4 with the Dura-Max 6.6L and Allyson Transmission or the GMC TopKick 4500 with the same engine and tranny.

    I know that the TopKick will turn around in a 34.4'area on the 2WD model. I am not sure about the 4x4 but I have not been able to find any information on the GMC Sierra 3500 4x4. I would assume it could turn around in a smaller area but just how small? Anybody that has one know? Also, from what the dealer told me, both trucks get approximately identical fuel mileage. Can anyone confirm this?

  • pescadorpescador Posts: 7
    Check out the steering specifications tab on the following URL:

    GMC should be the same. 53.5 feet for long bed crew cab 4x4.
  • brian45brian45 Posts: 1
    Amsoil suggests to use the Amsoil after a 5,ooo mile mark in the Duramax. Check the website. It has some good info on it.
  • pescadorpescador Posts: 7
    I am aware of Amsoil's recommendation. I was hoping to find someone with an unbiased opinion though. Does 5000 miles allow proper seating and break in?

  • I know that this may seem kinda off the subject y'all are on right now but I was wondering what performance programer would give me the most bang for my buck. I don't want so much power I'm going to start breaking things, however I would like my fuel mileage to improve. If anyone has any suggestions I would apritiate it. title
  • spademanspademan Posts: 14
    I bought the bullydog power pup for my 01 duramax and I love it. It has four power settings, and a specific economy setting. I did lots of research before I bought, and this was the one, plus you can find good deals online.
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