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Chevy Silverado and GMC Sierra Duramax Fuel Mileage



  • If any one could help me, that would be great? Im thinking about buying a Duramax Diesel, but dont know if it is worth it. I travel alot ( approx. 200 miles a day ). What is the average MPG's on 2003, 2004, or should I look @ a different year? I was told the '03 and '04 in the 6.6 liter were the best, is this correct?
  • hoots10hoots10 Posts: 1
    I found your RE very interesting as I have your identical truck, just in a GMC. You sound like you know quite a bit about your truck, and as a first time diesel owner, I have some questions. I also went with 285's and raised the front end by turning up the torsion bars. The truck really looks like a truck now, but my problem is the front end is loose and rides rough. I think I need some longer/bigger shocks on the front end. Any comments? Also any recommendations on oils (synthetic vs. conventional), oil filters, length of oil changes would be appreciated. I currently us Mobile Delvac, AC Delco filter, and change every 5K. Can I run the oil longer? I'm also interested in putting an exhaust kit on. Does it void warranties and what benefits am I going to get? One last issue and I'm done. I was getting 18-19mpg at 65-70mph, but as I've gotten over 10K miles on the truck, my fuel economy has dropped 2-3 mpg...Is it time for me to put a new fuel filter on? I currently have 14K on the truck. I've been nothing but completely satisfied with the power, fuel economy, overall performance. And to think I almost bought a dodge. I'll never go back to a gasser or anything but GM. Forever DIESEL!
  • dddtdddt Posts: 13
    I have a 06 DD and bought the Superchips Flashpaq Tuner #2805. It does give you more "get up and go" but does nothing for the improved gas mileage especially while towing.
  • dddtdddt Posts: 13
    Anybody have any advice on how to get better mileage on the 06 DD 2500 while towing??? Or is 12-14 the best it gets. My brother in law has a Ram cummins and gets 16-17 towing the same weight as me. Any suggestions????????
  • dddtdddt Posts: 13
    Anybody have any advice on how to get better mileage on the 06 DD 2500 while towing??? Or is 12-14 the best it gets. My brother in law has a Ram cummins and gets 16-17 towing the same weight as me. Any suggestions??????
  • dddtdddt Posts: 13
    I have a 06 DD 2500 and get the average 17-19 city/highway combo driving. I once got the reported 21 mileage that you hear people talk about,BUT, I was driving the whole tank at 60 mph. "That is not how I drive." Towing I get approx. 12-14 towing a 7500 Travel Trailer, depends on the terain and head wind.

    I now have 18000 miles on my baby and pray that at least the towing mileage increases, if not, should of bought a Ram Cummins like my brother in law who is getting 16-17 towing the same weight as me. Go figure!!!!!!!!!
  • dddtdddt Posts: 13
    The big mirrors on the 3500 don't allow them to electronically be brought in. You must push them in manually. I had the electric ones on my 05 2500, they were wonderful, but they were samller.
  • exrenchexrench Posts: 2
    I just bought my first ever diesel truck 2007 3500 duramax 360hp, 650tq. I got 18.2 my first my third tank I got 14.7. I only have 1100miles on it now. I thought maybe a baffle in my muffler broke loose inside because of the hiss noise coming out the tail pipe at idle. I am not at all familier with diesels and dont know what to expect. I travel 25 miles to work at 40mph. I bought it to tow a 14,800lb 5th wheel. I was told the hissing is normal, and to wait a while before deciding about the mpg..
  • hunter80hunter80 Posts: 3
    Just wondering if anyone has either one of these and if so which is better and does it really help on MPG. Just trying to get the most I can on MPG.

  • coontie57coontie57 Posts: 128
    I had an edge on my ford diesel 7.3 and I could not see it helped the fuel mileage... lots more power thought.
  • likearocklikearock Posts: 13
    I have a friend that runs a tire store and they turn up the torsion bars on these trucks pretty frequently, and I asked him what was the most he would recommend. He said not to go more than 1.5 inch higher or you will sacrafice the ride, he said you needed to get the $300.00 kit if you wish to go higher. As far as the oil is concerned, I run Amsoil heavy duty/ marine diesel synthetic , I became an amsoil dealer just so I could buy the oil and other products for myself and family. I also run Wix or Baldwin oil filters, The oil is a 25,000 mile change interval but I only run mine 14,000 and change the filter at 7,000, As far as the exhaust kit, I think that will probably affect your warranty,I think the air filter is probably a bigger culprit on robbing fuel mileage,my mileage also suffered a little before I installed a new air filter. the truck came with a good Donaldson Air Filter I replaced it with a K&N air filter on mine, I can't really claim that it added much to mileage other than it increased it back to where it was previously when the truck was new.I do Change my fuel filter about every 15,000 to 20,000 miles, As you know, diesel tends to have a lot more trash,
    Hope this info helps you out.
  • likearocklikearock Posts: 13
    I get about the same mileage towing as you do with my DMAX
    I pull a 11,500 lb High profile 5th wheel, Mine is more constant around 12 mpg depending on terrain and wind,
    I would like to have a dodge like your brother in law does, we had 2 Dodges a 2004 and 2007, both with turbo cummins, Pulling the same load they got 10 to 12 mpg. They were both good trucks but never got anything close to that pulling.
    I wish for higher mileage towing as well, but I think thats about what we are going to get.
  • likearocklikearock Posts: 13
    Try Dave Smith Motors in Kellogg Idaho,
    Really super deals and he will deliver for a very minimal cost.
    He sells Chevys, along with Dodge.
    Saved several thousands of $$$$$$ even with delivery to lower Alabama.

    Hope this helps
  • sullyaksullyak Posts: 30
    I am going to purchase my first diesel truck this month. I have read a great deal about Ford, Chrysler and Chevy's diesels. I have narrowed it down to the 2007 chevy with the Duramax or the new 2007 6.7 liter Cummins(supposedly out this March). My question is regarding fuel mileage. It appears from this post and others that the cummins has the reputation of providing significantly better mileage. Would you agree with this? It is especially important for me because in addition to towing, I will be putting several thousand miles/yr of unloaded highway driving. Any opinions on unloaded highway fuel mileage between the Duramax and Cummins would be greatly appreciated as well as general opinions regarding durability and features preferences between these two.

    Thank you.
  • coontie57coontie57 Posts: 128
    A friend of mine bought a 2006 Dodge in Feb 06, That diesel PU has a 6 speed manual shift transmission. Based on his POOR fuel mileage I bought a Chevy in July 2006. I am not sure he has ever beaten 14 or 16 mpg unloaded. I have gotten a pinch over 20 a few times and about 11 pulling 12000 lbs... Now a Dodge might do better with an automatic transmission but it might not..

    On my friends first trip with just a few thousands on it he got 11 mpg empty.. From Ohio to central FL..

    The auto in the Chevy is really nice... I like that 6 speed auto. It slows you down on hills really nice.. You would be impressed.. After having a 1999 250 Ford Diesel I was !!

    One thing I noticed is the visiblity from inside the vehicle to the outside. It seems to me that the Ford was better. When you go back to look again see if you can see it. I might be my height vs others but it seemed real to me.

    I am not sure about the Ford though since the engine is new again..Their 6L engine they came out with in 03 sure had lots of problems early on..
  • cinnesscinness Posts: 1
    What leveling kit did you use? I've been running Bridgestone 285/75/16 and want to go with some 315/75/16 BFG's. I went with the Bully Dog Pup hoping for better fuel mileage. The power was awesome but no noticable fuel improvement. I'm only using the tire calibrator feature of it now and running stock.
    I started out 17 MPG highway empty, but the biggest improvements noted was switching to Mobile One Turbo Diesel 5w-40 oil, using a good grade of diesel, Exxon, and believe it or not, setting tires at 50 psi made a noticible differnce. I'm now averaging 20.2 @ 42,000 miles. The Mobile One resulted in an immediate 1 MPG increase. K&N filter no improvement.
  • dddtdddt Posts: 13
    Can't really speak for the Cummins but for the DD you should get about 18-20 on the highway non-towing. About 12-14 towing depending on the terrain and wind. The power is awesome and it makes climbing hills a breeze, not going over 1800 rpms while towing. I put the superchip flashpaq tuner in mine this past weekend and i got approximately 2-3 mpg more on the highway which is wonderful. Towing does absolutely nothing for mpg but gives you more power, "like you need more"!!!! DD better product long term, but with my brother-in-law getting 16-17 towing and 18-20 not, sometimes I wish I would of got the Cummins; but got to look at the big picture!!!!! DD by far a better product!!!!! Good luck with your choice.
  • dddtdddt Posts: 13
    I have the 06 DD 2500 HD 4x4 21,000 miles on it, I put the K&N air filter and the superchip flashpaq tuner. With these two I now get about 20-22 mpg empty. (absolutely no difference towing.) My speeds are between 65-68. 70-75 I get about 19-21 mpg, 75+ 17-19 mpg, all depends on the terrain and wind. If you get the superchip be careful when you press down on the accelerator, it really does get up and move!!!!!!! Raced a mustang convertible the other day stop light to stop light.........smoked him. This is probably why I can't get higher than 22 mpg. Wonderful product, but what I wanted was something to give me better mileage while towing. Hope this helps.
  • codykcodyk Posts: 5
    I currently have a 97 ram 2500 4wd 5.9 magnum xtended cab auto with o/d that gets a whopping 12 unloaded and at best 9mpg pulling a 16 foot steel stock trailer with two to three horses.Guesstimate 6500-7000 pds. and I am probably way overguessing on wt.I'm trying to find ways to improve mpg such as possibly adding lockout front hubs or if the expense of a diesel is the way I should go I have been looking thru posts on mpg and see the old gundeck variants {random mpgs from 12-25 with same brandse.g. dodge,chevy}I need a4wd so that is a given and as everyone else want the best mpg. I understand that I will want a high geared rearend and o/d tranny. I will be pulling the above mentioned wt. and running empty.I live in oklahoma and will not be pulling in mtns. etc. mostly flat to rolling hills, however one doesn't always know where the road leads. I have also read about the ulsd failures due to the lsd acting as a solvent. If there is anything else I missed please let me know and also please give advice. any and all is appreciated.I have a friend that has a duramax after his 2500 2wd cummins was totalled ,that recommends the cummins. He got 21-22 empty and16-18 pulling a 22 ft steel gooseneck with 2-3 horses. thanks in advance
  • sbritchsbritch Posts: 1
    Last August I bought an 06 3500 dually duramax. Love the truck and power, disappointed with mileage. I installed a 4" exhaust and air filter. I am getting 13.5 to 14 mpg. any suggestions. I tried using Power Services fuel additive, and everytime I do the check engine light comes on.
    Also, anybody know if the exhaust change voids any warranties?
  • I just purchased a 06 duramax and I am not getting good mileage with it. When I purchased it with 5500 on it I was getting 17 but now with 10000 I only get 13-14mpg(Empty). Does change much with a 24ft gooseneck behind. I have been not be able to figure our why the mileage decreased so much since I have owned it. I have changed filters,oil and air(K&N)and there was no difference. Please help with suggestions. Thanks. P.S. I am new to the site, how do I post a comment without having to reply to someone?
  • edlegueedlegue Posts: 6
    Hi all,I am considering a GMC Duramax diesel and was wondering whether there is a significant difference in the mileage between the 4wd and thw 2wd? I will be towing a 5th wheel on occasion but generally I won't need a 4wd. I am kind of thinking that if the mileage difference is not significant, then I might as well get the 4wd. Dad use to tell me "It's better to have it and not need it, than need it and not have it" This is my first diesel so I am a little nervous to spend the $. Thanks
  • coontie57coontie57 Posts: 128
    My first diesel PU to pull my 26 ft Jayco was a Ford 250... in 2 x 4 drive. I never really had a problem without but I had to be careful. The only time I got stuck was in my yard when I tried to pull the boat up and out of my storage space in the spring when the earth is soft and squisshy... I had one wheel ON the asphalt but the limited slip didn't help and I had to get the OLD chevy out to pull me out of the mud. In July 06 I bought a new Chevy Duramax with 4 X 4 and don't regret it. You won't either the first time you come into a campground that just had a flooding rain and you are anxious about the soil. I have been there several times ... I now have a 29 ft Holiday Rambler and the Chevy pulls it just fine. Two of my friends have also purchased this vehicle and they are all in 4 x 4.. You just never know what you are going to get into in a far off campground.
  • dddtdddt Posts: 13
    I have a 06 DMax 4x4 and my friend has a 06 Dmax 2x4 and there is really no difference in the mileage, so obey your dad and have rather than not.
  • dddtdddt Posts: 13
    Bro you have a problem with your truck. I have a 06 Dmax 4x4 and I have gotten between 17-22 mpg since the day of conception. Difference being with the 22 mpg I had the Flashpaq Superchip tuner in it. But I have never gotten less than 17 empty. Towing well different story......between 11-14. Have your vehicle checked unless your doing a lot of short distance driving and turning your truck on and off a lot. That will definetly have an effect on your mileage. Hope this helps.
  • wcannada1wcannada1 Posts: 2
    What kind of MPG are people getting in the new 2007 Duramax?
  • exrenchexrench Posts: 2
    I got the 07 Duramax 3500 single, got 18.2 city, first tank. Then I heard this loud metallic pop noise one time and have been getting about 15.8 max city, 17 hwy, I suspect some kind of baffle somewhere broke lose in the muffler and may be causing partial blockage, but the gauges tell all is good like temp, oil press, etc. I also have a vibration on moderate heavy acceleration from a dead stop, maybe the t/converter, goes away right above 1200rpm. Have not had the chance to have the dealer look into yet...I have not added a single aftermarket item. only 6500miles.
  • pete59pete59 Posts: 6
    I am looking at purchasing a Chevy 2500HD Duramax with Allison tranny. Going to stay with 2 wheel drive because 80% of the time I will commute 110 miles/day without pulling camper and boat. I am interested in the fuel economy with this setup. Anybody know what to expect?
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