Ask the Car People.SM


Chevy Silverado and GMC Sierra Duramax Fuel Mileage

620 messages,  Last post on Dec 15, 2012 at 3:45 PM

You are in the Chevrolet Silverado & GMC Sierra Forum.

What is this discussion about? Chevrolet Silverado 2500HD, Chevrolet Silverado 3500, GMC Sierra 2500HD, GMC Sierra 3500, Diesel, Fuel Efficiency (MPG), Truck

Messages Page 62 of 63

#603 of 620 vibration in 2011 2500hd by jimnothappy

Apr 26, 2012 (9:11 am)

I have a vibration in my truck, back to dealer at least 9 times now, no fix, i have 2100 MILES ON IT and i am getting tired of getting the run round . is there a fix

#604 of 620 Re: vibration in 2011 2500hd [jimnothappy] by gmcustsvcsarah

Apr 26, 2012 (9:45 am)

Replying to: jimnothappy (Apr 26, 2012 9:11 am)
jimnothappy,
 
I'm sorry to read that after making so many different trips in for this to be looked at there has not been a satisfactory resolution for you. If we can follow up with your dealership on this, please send us an email at socialmediagm.com with more information (your name/Edmunds username, phone and address, the last 8 of your VIN and current mileage, the name of your dealership, and number of times you've been in for this same concern). My coworker Christina will advise you further.
 
Thank you for your patience, and we look forward to hearing from you,
Sarah
GM Customer Service

#605 of 620 Re: vibration in 2011 2500hd [jimnothappy] by kacansas06

Apr 26, 2012 (12:51 pm)

Replying to: jimnothappy (Apr 26, 2012 9:11 am)
You might take it to a place that does over the road (the big semi's) tires and have them check tire balance. I don't think tires are covered under the warranty. Happy hunting.

#606 of 620 Low economy by pmeinscher

Aug 18, 2012 (5:29 pm)

I have 2007 chevy 4x4 dura max with a milage at about 12 miles per gallon. Was wondering if this unusual or not for that truck I was hoping for much better than that.

#607 of 620 2009 Duramax 2500 by nater37

Sep 15, 2012 (8:51 pm)

I am very disappointed after owning my dmax for 4 years and only having 22000 miles on it. I get 17.5 mpg empty. I pulled my dads camper to New Mexico this week and pulled it fine, but got 5.6 mpg both ways and it did not matter if I pulled 65 to 75 mph. I thought it was because I pulled it to mountains full of gas and water but empty on the way home and was not any better. The camper only weighs around 7000 lbs. called the dealer and they asked when I had changed fuel and air filters and how much the wind was blowing. The 6.7 Ford is starting to sound nice , although my dads 2012 duramax gets 12 pulling same trailer

#608 of 620 Re: 2009 Duramax 2500 [nater37] by gmcustsvcsarah

Sep 16, 2012 (10:02 am)

Replying to: nater37 (Sep 15, 2012 8:51 pm)
Good afternoon nater37,
 
I see you've checked in with your dealership on this; if you want for us to look into this further with you and your dealer's service department please email us the following information at socialmediagm.com: your name and Edmunds username, phone and address, the last 8 digits of your VIN and current mileage, and the name of your involved dealership.
 
Sarah, GM Customer Service

#609 of 620 Re: 2009 Duramax 2500 [nater37] by kacansas06

Sep 16, 2012 (11:45 am)

Replying to: nater37 (Sep 15, 2012 8:51 pm)
A lot of this kind of fuel mileage problem comes from the driving method. I believe your truck has a tachometer like my 2006. When you accelerate with a big load do not wind the engine to high, say 3000 to 3500, RPM for all it accomplishes is using lots of fuel. When I am towing I rarely let the RPM exceed 2000. When driving without a load I take the RPM at speeds under 35 to 2000 or so and after that take my time and keep the RPM below 1800. Think of it this way, that 6.6 liter engine is more than twice the cubic displacement of a 4 cylinder engine. 4 cylinders go to 3500 to 4000 RPM or more all the time for shifts. So divide that by 2 for the diesel and you get your target RPM ranges. I recently took a fishing trip with 21 ft boat loaded and the truck heavily loaded and made 24 mpg going up north and 22 mpg returning at faster speeds. Oh yes, these truck do not like being pushed to 65 or 75 while towing plus the trailer tires are usually rated for a Max speed of 55 to 65(look at the tire sidewall). I tow our big boat, 17,000 lbs at 13 feet high by 10 feet wide by 45 feet long triple axle, at highway speeds of 55 to 60 cruise and max downhill of 65mph. Doing that I get between 12 to 16 mpg depending on terrain.

#610 of 620 Re: 2009 Duramax 2500 [nater37] by coontie66

Sep 17, 2012 (2:31 am)

Replying to: nater37 (Sep 15, 2012 8:51 pm)
I think that there are at least two things I would like to recommend as possible answers to your post.
 
The first thing is that your Duramax is not broken in yet and probably won't be for another 30K miles. Patience!
 
The second thing is that it seems to me that speed and MPG are inversely related. The faster you go after a certain point the worse the MPG.
 
About 6 weeks ago I drove to Winston Salem 150 mile drive and kept the speed on 62 mpg and got 20.2 mpg that was when my 06 Chev just turned 50K. Prior to that time I was getting 17.8 MPG after GM replaced the turbo. The new turbo (probably what you have and much better they told me) actually reduced MPG about 2 and that was back 1.5 years ago. The Chev got in the 20 range when new but not after the new turbo until 6 weeks back.
 
Some where you can find the power curve graph for OUR engine. See if you can drive where the power HP and Torque are at its maximum for a certain engine speed measured in revolutions per min. That number will be around 1750 RPM's and will be 60 and 65 miles per hour.
 
Keep driving and it will just get better but don't expect it before the engine is broken in.

#611 of 620 Sweet spot by jerrydock

Sep 17, 2012 (8:41 am)

Find the sweet spot for your engine. I have a 2005 and 1700RPM is where it likes to be. My wife has a heavy foot and she never gets good mileage from the diesel; so I keep her in the Geo Metro as much as possible.

#612 of 620 Sudden lose of mpg on 2007 Duramax 2500 HD by rbboyd

Oct 06, 2012 (4:02 pm)

I bought a 2007 Duramax a month ago and it was getting 15.9 mpg on trip home. I put the chip in it and my fuel dropped to 13.5 mpg. I pulled a small camper trailer approx. 400 miles and got 9.9 mpg. After I quit pulling trtailer just going back and forth to work I am still getting 9.9 mpg. That was with my H&S chip set on "Hot" and not getting into it. I have it turn completly off now to see what happens. I have new fuel filter. Truck has 20" rims & has 6" lift on it. Any suggestions?

Messages Page 62 of 63

To POST a message, please Sign In.

Advertisement

Browse by Category

Browse by Vehicle
   View All Vehicles

Browse by Board
Browse by Topic
View All Topics

Edmunds Community

Advertisement