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Chevy Silverado and GMC Sierra Duramax Fuel Mileage

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Comments

  • vanhorn_svanhorn_s Member Posts: 2
    gm issued an update for those hoses, and they still leak. i have heard estimates of $1200 to replace all 3 lines.

    there is an aftermarket update available at http://www.redsautorehab.com/products.html
  • catamcatam Member Posts: 331
    Where did you hear that estimate????

    All 3 lines are about $100 and maybe 1 hour labor, shouldn't be more than $200 anywhere.
    There is a TSB on these, many dealers will replace them at no cost under the 100K drivetrain warranty as well.
  • kacansas06kacansas06 Member Posts: 33
    Most common problem I see in fuel mileage on these vehicles is that drivers trust the computer to give them accurate mileage. I calculate it based on miles driven and fuel put into the tank at the fill. I stop at the same point each time when filling since it is easy to look in the filler neck. When towing 18,000 + of sailboat and trailer in mountain country I turned 9 to 9.5 mpg. Same rig on the flat prairie gave me 13.5 to 14 mpg. I turned the better mileage when I slowed to 57 mph. When I drive around the cities(Twin Cities, MN) I usually get 21 mpg without any load. Highway mileage is always with some load and gets 23 to 24 mpg depending on headwinds. I find that my '06 Duramax does not like to be driven over 68 mph. I hear the engine working harder and mileage drops to 22 mpg. At 75 mph mileage drops to 19 mpg. The '07 1/5 through '10 Duramax does have somewhat better aerodynamics but that plus is offset by the tuning in the engine so getting over 20 mpg is harder. When I drive back country roads at 55 mph I can exceed 25 mpg unloaded.
  • sm_racersm_racer Member Posts: 1
    I think many of the milage issues with Diesel trucks are from people moving over from gas powered vehicles. To get decent milage from a Diesel you have to keep the speed way down ie. less than 70 and get used to crawling away from stop lights.

    I was totally disapointed when I moved from a 2006 Tacoma that was getting 17 city and 23 hwy to my 2009 Silverado Crew Duramax. If I drive the truck like any other vehicle or my previous truck I get 14-15 city and 16-17 hwy. The best I can get out of my 2009 while milking the [non-permissible content removed] out of it and pissing everyone off around me is 16.5 city.

    Previous truck was able to tow and get 12 while the new chevy gets 9.5? Gone are the days I could tow at 75 or 80 as well.

    I think many of the claims here are exagerated or from older trucks with out the DPF system.
  • andeyhallandeyhall Member Posts: 1
    I'm just looking on here to try and find out mileage for 6.6 duramaxes for my dad....he's thinking about getting an '04. I'm a powerstroke guy myself. I'm not here to start anything about that, I just noticed you have an Edge tuner. I'm definately not a know-it-all when it comes to diesels, but I stay in Powerstroke forums A LOT! I've done a ton of research on tuners as I am looking to get one myself. From what I have read so far, Edge tuners are simply trash. They do not tune the transmission, which is not good for your truck at all, and from what the guys tell me also, canned tunes (pre-loaded tunes) are not good for you truck either. Most everyone recommends SCT with custom tunes. Just thought I'd pass my research on. Again, not trying to start anthing.
  • jerrydockjerrydock Member Posts: 29
    One of the joys from driving a diesel is being able to "smoke out" the jerk who tosses his cigarette butt out his/her window. I get next to them and nail the pedal; works wonders.
  • kacansas06kacansas06 Member Posts: 33
    The tailgater who is trying to get your truck to run 10-15 mph over the speed limit on a city street because his rice burner can't accelerate if he slows down. The he follows me onto the ramp for the interstate, I floor it and a 1/4 mile later at 65 mph(speed limit) I look back and he is just finding his way through the smoke. Somehow I get a lot of room around me for awhile.
  • kacansas06kacansas06 Member Posts: 33
    As I have said on the and so have many others it is all in the way you drive. I do not try to cruise my 6.6 diesel at 80 mph because it guzzells fuel at 17 to 18 mpg. However if I run 65 to 70 I get 20 to 22 and running on slower highways at 55 to 60 I get 24 to 25. City mileage is 19 to 21.
  • byurunrbyurunr Member Posts: 1
    I'm new here and have been reading some of your posts. This the first I've heard of "leaking trans lines" (Post 513 is Scary). I've NEVER had a leak, period.. I am @ 118,760 for miles, fourth set of tires, third set of front shocks, second set of front hubs (305-70-16s). Tire "noise" post, had that, tires had "cupped" causing very rough ride and plenty of noise. Changed to less aggresive tread but still same size. Cupping primarily caused by lousy alignment(s). Mileage, have to agree with various posts RE: Leadfoot, giulty myself, from rice burners to mustangs ALL have that same confused look when they see your back bumper pulling away.
  • artgpoartgpo Member Posts: 483
    I am getting 20 mpg on the highway at a steady 72 mph and between 11 - 12 mpg towing my 11, 800 lb 5th wheel. Mine is a 2009 2500HD Crew Cab, long bed with the Duramax/Allison powertrain. These are real mpg results using a calculator and not the Driver Information Center, however, the DIC is very close to the calculated results.
  • kacansas06kacansas06 Member Posts: 33
    I have had the same problem with alignments. Once you go slightly oversize or more on tires most shops don't know how to align it properly. I found one that has the experience and knowledge in the fall of '07 and now I finally need an alignment again. I think each change in tire brand needs an alignment. I saw the other post about 20 mpg at 72 mph with an '09 and that is about the best I have seen for that model year. I also read his DIC was close to correct which mine has never been close at all. I now ignore the mileage reading and just calculate it.
  • akjbmwakjbmw Member Posts: 231
    edited May 2010
    I think I remember reading when the mpg displays first arrived that the values were not a straight miles driven divided by gallons used. It was weighted by periodic history rates averaged with more frequent current rates.
    Anyone know how it is calculated now?

    I like that our '06 Impala LS computer has both an instant mpg AND an average mpg display. Our '07 2500HD Duramax LTZ only has an average mpg display, but we get a gallons used display.
    As a "detail oriented pain in the butt quality assurance professional", I can still accept the "close enough" readings. It all sort of falls into the "What is really important" category. If the factory displays aren't good enough, we have to decide how much it's worth to us and add big dollar aftermarket measuring gear.
    I get real values from the spiral steno pad that lives in the truck. I record date, odometer, trip miles, $/gal, # gal, $ spent, brand, location, and misc notes at every event. Events are everything from fuel to light bulb replacements (bulbs don't get fuel information recorded). What do you expect, I am in the QA field.
    Mostly, this has been of value to figure out when we went where.

    Loving my 'Max.
    We call it Max, and the outdated navigation system voice Maxine...
  • blp2blp2 Member Posts: 1
    What is the nomal fuel rail pressure for a 2006 Cherolet 3500 Duramax?
  • uyholidayuyholiday Member Posts: 1
    I have a late '06 2500HD. I have replace each of the tree lines, and one twice. My diesel guy says that he can not keep enough lines in stock. But... I love my Duramax. Dirving highway without a load @ 68mph (1700rpm) I get 21.5mpg. Pulling my 5th wheel, 12mpg.
  • kacansas06kacansas06 Member Posts: 33
    I have an early '06 with no tranny or line problems ever. I think I have gotten lucky Driving highway w/o load @ 62 mph at 1500 rpm get 24 mpg(actual not DIC) and pulling 18,000 lbs of boat & trailer 15 mpg at 55mph It's good enough!
  • sixelksixelk Member Posts: 2
    Hello I have just found this website and read your part of this thread, So i am looking for a few answers please. I am looking at a 2007 GMC duramax in mint condition really lows hours BUT it has 125,000 miles on it can you tell me what to look for when I go look at this truck? ( injectors,hubs, Idle, smoke?etc. ) or what ever else could be coming up as a repair I have always had the 1500 gas 5.3 engine I am tired of having no power when a little hill comes up. any suggestions would be greatly appreciated thanks Oh yeah there asking $26,000
    Rick in colorado
  • kacansas06kacansas06 Member Posts: 33
    I can't figure out how it could be low hours but high mileage unless it has had an engine change. Get the VIN number and ask a dealer about it's repair history. The most accurate method to get the history.
  • sixelksixelk Member Posts: 2
    the dealer says all higway miles?
  • rseeborseebo Member Posts: 12
    I had an 05 GMC 2500 and got rid of it after just 3 years. I would tow a toy hauler at about 12k going 60 - 65 and got decent mileage, 11mpg or so, but it would constantly over heat. Took it to GM many times and they said the airflow is good and there was nothing wrong with the truck running at 220 avg.. I had added the Banks 6 Gun on it and it helped to reduce the heat a little, but it would still get very hot going up hill with all kinds of Ford's running by me with their air on at 65+. Needless to say, I bought an 08 2500 and have had no problems with it. I towed the same toy hauler from California to Georgia with about 14k between bed and trailer and the thing was awesome. I got 11.5 MPG's and it cruised the whole way here. I get about 15 - 17 MPG on the city streets with minimal idle (about 14 in traffic) and upwards of 20 - 22 on the highway at 70 MPH. I love this truck in comparison to the 05 and would not trade it for another.
  • rseeborseebo Member Posts: 12
    Can anyone tell me if you can fit a 285 on an 18" wheel under an 08 - 2500 HD with only a leveling kit? I have heard that the newer body style is not so friendly with the bigger tires on the inner wheel well and they rub. I have also been told they sell a kit that you can buy to "trim" the area that it would rub on and make it look stock after the modification?
  • akjbmwakjbmw Member Posts: 231
    See post #77 under "Chevy Silverado and GMC Sierra Tires and Wheels" in Pickups. The shop probably used a hammer. I was glad to not have the rubbing any longer...
  • coontie66coontie66 Member Posts: 110
    I started having trouble with my 06 Chebby diesel back in Jan 10.. The check engine light kept coming on and the local Chevy dealer would do some fix and it would work for another few weeks or months. The best fix was back in Jan when they took off and cleaned the turbine blades I think it was. Since that first incident the fuel mileage has decreased and the truck has been in the shop 5 times and is there today. They finally had the computer give them the correct code that it was the turbine after all and one is on order now. It should be in and on the PU by Monday. Now the mileage should return to 21 mpg highway and 16-17mpg around town. Wonder what a new turbo costs? $4-5K is my guess.

    What's yours?

    Ps in Jan the PU had 34K miles on it and 38800 now..
  • coontie66coontie66 Member Posts: 110
    I like that myself but its harder to do NOW with that nasty new Diesel Fuel........

    I liked to do it with my Ford Diesel to them darn bikers in yellow shirts that clog the roads.
  • zman804zman804 Member Posts: 2
    I have an 06 Duramax LBZ with 50,000 miles on it now and i can't get anymore than 14-15mpg city or highway. When i first got it i was averaging 17mpg city and over 20 highway. The dealer claims there is nothing wrong with it. Does anyone have any idea's.
  • kacansas06kacansas06 Member Posts: 33
    I do know that the fuel you buy now has a lower sulfur content. This means less power and less lubrication. You can buy additive or look for other alternatives. i add just a little engine oil to my fuel in the summer and mileage goes up. Also tires play a big part. make sure you have same as factory spec tread width and at least the same diameter but not more than an inch larger, 30.5 to 31.5, for that initial mileage. Also run synthetic motor oil, Mobil one seems to be best. Lastly do not run it over 66 to 67 mph. Do everything you can to keep it in 6th lock up or 5th lockup. They didn't tell you but they changed the tranny programming so it doesn't upshift as soon as when we bought the truck. I have mine back up there using these tricks and can get 22-24 on a 60 mph cruise without cruise control even better.
  • zman804zman804 Member Posts: 2
    I have been using Mobil 15-40 since new will the syntheic oil make a big difference?
    I did put 265 tires on it but my fuel mileage dropped before that. Did you ever have a vibration issue with the 06's I had it back several times eventually they put new cab mounts on the truck, I think they used a softer mount to absorb the vibration?
  • donh220donh220 Member Posts: 1
    I have a 2001 Chevy Duramax with 150k miles. At highway speeds and under a pull, loaded or empty and more when loaded, it will defuel and will not get over 1900 rpm's. It still has normal power until that mark, then its done. Never does it around town. When in this mode, if you try to accelerate it will act as if its downshifting with no power. I have to turn the engine off for a couple minutes then it will have full response. Then the next hill or pull it does it again. I will add that during the winter it hardly does it. The injectors and/or fuel filter being replaced made no difference.
  • coontie66coontie66 Member Posts: 110
    I had a Ford 250 diesel that would defuel... but my duramax hasn't so far. I think you need to invest in a exhaust gas guage and see what's going on. I can't remember what the max temp is but as I recall around 1600 F.. If the turbo gets to near the max you can burn off the tips of the turbos... then it gets ugly. Driving to AK I had to watch the exhaust gas temps on some long climbs........
  • pdguttenpdgutten Member Posts: 1
    I had the same problem. I recently changed the fuel filter and realized the filter lost its prime. I am back to 18 mpg highway. It is easy to loosen the screw on top of the filter and make a few pumps to insure your filter is primed. Good luck!!!
  • shortty603shortty603 Member Posts: 1
    My 2003 Silverado is leaking coolant, seems to be in front of motor. Any one have any ideas?
  • 052500hd3052500hd3 Member Posts: 2
    Have you checked your MAF sensor?? I had a very similiar problem with my 05 and found that there was a loose connection on a aftermarket part that I installed that was killing the power to my MAF sensor making the Computer defuel since there was no air..
  • 052500hd3052500hd3 Member Posts: 2
    The over heating problem you had was about a 200 dollar fix, It is the turbo inlet (mouthpiece), I have an 05 my self, and I honed out the stock and finally bought a new aftermarket turno inlet. I also have the Banks Six gun and the Ram air intake. I have had no mechanical problems with my truck and I have about 114K on it. the Trans will prolly need to be rebuilt shortly but it only slips on the 4-5 Upshift at 90MPH when I have the Banks on Speed Loader. It has been a great truck!!
  • lnjbarbosalnjbarbosa Member Posts: 1
    I have an '05 Silverado 3500 has been struggling to start sometimes. Now it does not
    want to stay running, acts like it's out of gas and actually died out on the highway. Tried changing the fuel filter and it didn't solve the problem, it died out again. Any ideas on what else to check?
  • kf4urukf4uru Member Posts: 2
    edited August 2010
    I'm looking to buy a disel truck but am having a problem weeding through the info. Seems I can find info to support whatever I want to buy!!! Used is fine, so what is the truck that has the best engine and year? I want duribility and capacity. Any help out there?
  • kacansas06kacansas06 Member Posts: 33
    2006 Duramax with Allison six speed however there is great demand for these so finding a good one will be hard. Mine is NOT for sale. Also get the VIN number and then check through a dealer or GM direct on the major maintenance factors: fuel filter changes, oil changes, Transmision flush every 36-40K miles. Look for Proof of these! Do not buy one that has been "chipped". These trucks came with 6 year 100,000 mile powertrain warranty. Good luck.
  • kf4urukf4uru Member Posts: 2
    Thanks. The only experience I have with disel was a 99 Volvo road tractor with a cummins disel, love the cummins but it seems the only truck with it is Dodge and I dont hear good comments about Dodge.
    Thanks again for your comment and any more are welcomed.
  • coontie66coontie66 Member Posts: 110
    I see someone beat me to the post... but my 06 Silverado with the same tranny as mentioned is great. I live in the MTNS of WNC... My camper is only 12500 lbs but its an easy pull up our largest mtn here. 7percent grade for miles. You can't tell that my 21 ft bass boat is even there

    I just had the first real repair to it at 38K miles and still under warranty it was a new turbo... around town mileage back to 17+ and road 21mpg. Heated seats are nice in the winter. XM radio is hard to beat.
  • dixmax1dixmax1 Member Posts: 1
    I have a 02 'max' 90K miles, got 9-10 MPG pulling 36' 5th wheel. I keep EXACT fuel records. 10.3 overall MPG on Alaska trip of 9000 miles. Friends with Ford power stroke got 10.7. Bobtail we get 17. When it was new, it has a smoke problem but went away after numerous trips to the dealer. They never found anything wrong.
    Good Luck
  • hillsdale56hillsdale56 Member Posts: 15
    Hey everybody maybe I can help. I have an 06 hd serria 4wd w/373. The best I ever saw around 21.5 unloaded. Please take note I live in new york, land of taxes and hills. I run the taconic parkway, real hilly. On average I get about 370 miles to a tank. Combined city, and highway. Then I bought a tuner from powerup diesel. Biz. Dude used to work at gm. After installing tune I did 470 miles on a tank. I paid 421 bucks for the tuner. Check it out see what you think, hope it helps. Keep those injectors clean, at least every10,000
  • barrailbarrail Member Posts: 27
    I read your thread about beware of buying a truck that has been (chipped), Im thinking about chipping my 05 lly for mileage and Im concerned about the short comings. Any information would be greatly appreciately.
  • hillsdale56hillsdale56 Member Posts: 15
    Good morning everbody. Hey, I just took a look at powerup diesel . Biz. The tuner I bloged about is on sale for 427. Check the site out
  • jerrydockjerrydock Member Posts: 29
    I chopped my truck as soon as I got it. I can dial in economy or power. It saves my truck and my wallet. I suggest that the way the truck ahs been used and maintained is the most important thing to look at.
  • barrailbarrail Member Posts: 27
    went to powerup diesel and bought their programer. noticeable throttle responce on the lowest setting, but do to the cold weather, can't determine if mileage has improved as of yet. I just want to make sure how everyone is determining their fuel mileage. Gallons in, divided into miles driven. Not what the DIC average tells you. EVERY one I ask how they determined their miles and they're to content with just using the drivers information center. So far, my best mileage has been 17.5 hiway staying under 70mph on flat terrain with the stock settings. Stay tuned to see if the programer improves mileage.
  • barrailbarrail Member Posts: 27
  • hillsdale56hillsdale56 Member Posts: 15
    Hi everyone, merry chrismas to all. Glad to hear you have the programmer. Reprogram to the 60 hp setting. This is said to give best economy. Now a few facts about winter fuel. Where do you live? Is your fuel cut with kerosene? This is what is called 1d. Gives the fuel a higher cetane rating. Kerosene is 60. But lowers the btu of the fuel. You will get poor milage with this. Fuel quality varies from one pump. Brand and another. What year truck do you have, what gearing? Me I have 06 with 3.73 4wd. With the tune I have to drive In fifth gear. Get engine up to 1900 rpm. I'd say around 22, 23 mpg at 63 mph. As far as checking your milage, fill it to the top of the neck, drive and then recheck.
  • cbears85cbears85 Member Posts: 3
    Hi all, I'm not sure this is the correct forum. I have a 2004 GMC Sierra 2500HD. I have an Afe cold air intake stage 2 system installed. I am constantly getting a "check engine" light on all the time. No matter what I do the "check engine" is usually on. I have tried cleaning the air filter but to no avail. Every once in awhile the "check engine" light will go off but only temporarily. As soon as I accelerate the light comes back on. Someone told me it could be the max air flow sensor that is mounted on the intake pipe that comes from the filter and goes to the engine. Does anyone know what causes the "check engine" to stay on and is there a permanent fix? It is driving me crazy. Any help would be greatly appreciated.
  • coontie66coontie66 Member Posts: 110
    edited December 2010
    Exactly a year my check engine light on my 06 started coming on and never went off. Chev folks look at it 4 times or so and cleaned the turbo and other turbo related things until they replace it. Problem solved.

    You need to put it on the computer and see what the error code is.
  • kacansas06kacansas06 Member Posts: 33
    I think you have messed with a complex computer system. It could be you have too much restriction. I know the people who sell those systems say they flow better but do they have as big a stake in it working correctly as GM. Check the package or web site it will basically say use at your own risk. My 06 filter seems to let nothing through for the passage behind it is very clean. Just checked it less than a month ago. I have replaced the filter 4 times so far. I can not imagine changing the intake setup without other major changes such as new higher flow turbo along with intercooler, piping, manifold and electronics changes. One can get slightly better power by reducing exhaust restrictions which also leads to cooler EGT temperatures. My Guess would be you are having EGT problems which can happen with too much air(runs lean) or too little. A diesel is a simple engine but made more complex be the turbo. Messing with intake can be a route to turbo failure.
  • hillsdale56hillsdale56 Member Posts: 15
    I agree with the guy who told you to find out what code your getting. A thought I'm getting right now, clean your mass air flow sensor. Use either or carb cleaner. Engine OFF. SEE what happens
  • cbears85cbears85 Member Posts: 3
    Thank you very much for your input. My truck is not a diesel and does not have turbo. It has the 6.0L gas engine. With that in mind, I don't believe it is having EGT problems. Along with the Afe cold air intake, I also had dual Areo turbine mufflers installed. I don't know if that makes a difference or not. I guess I will need to get it on the computer to see what the error code is and then go from there. Again, thanks for you input and time.
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