Chevy Silverado and GMC Sierra Duramax Fuel Mileage

valdezvip · May 2006

Anybody have fuel numbers on the 360hp duramax.

bcheep · May 2006

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.

valdezvip · May 2006

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.

gemini5362 · June 2006

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

06blackduramax · June 2006

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.

rseebo · June 2006

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

highlander2 · June 2006

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

coontie57 · July 2006

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...

bob129 · July 2006

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.
Bob129

rseebo · July 2006

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.

pescador · July 2006

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.

pescador · July 2006

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.

coontie57 · July 2006

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.

kd7cao · July 2006

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?

Thanks!

pescador · July 2006

Check out the steering specifications tab on the following URL:
http://www.chevrolet.com/silverado/specifications/

GMC should be the same. 53.5 feet for long bed crew cab 4x4.

grabowsky · July 2006

Thanks!

brian45 · July 2006

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.

pescador · July 2006

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?

Thanks...

outbackson · July 2006

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.

Thanks....link title

spademan · July 2006

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.

outbackson · July 2006

Thanks for the tip!!

coontie57 · July 2006

I now have less than 900 on the new Duramax and today driving 250 miles in the mountains of WNC and VA and TN I got a solid 18.5 to ...19.0...

I can see no problem getting 20 or better when I get to the flat land. Take off slow... drive the speed limit or there abouts..Only hit 70 a few times and put her back on cruise at 60 or 65 depending on the road speed.

That's not bad at all. Talked to my friend with the 06 Dodge... 6 speed manual shifter and he is still getting 14.5 with 9K on his.

I hope and believe I made the right choice.

alex1640 · July 2006

In reply to gemini5362 -

thought you should look up my post in the "how to get better fuel economy w/your diesel" category.

While I don't have a new truck, the stuff my mechanic is selling me does do the job on my 2001 Duramax. I've been using it for the better part of 2 years.

hope this helps.

Re: How to get better fuel economy w/your diesel [madeinamerica] by alex1640 Jul 23, 2006 (6:42 pm)

Replying to: madeinamerica (Jun 03, 2005 6:16 am)

I have a 2001 silverado w/ the duramax engine and a little more than 103,000 miles. I'm a lead foot and use the truck for commuting from Sacramento, CA to Berkley, CA (about 80 Miles). Sythetic oil DOES help, but I have found it is NOT worth the additional cost. My mechanic is a dealer for D1280x and has been adding it to my oil and selling it to me as a diesel additive as well. I used to get 15.4 mpg cruising at 75mpg. I now get 17 to 20 mpg. it's way worth it and more than pays for itself for me. I am pretty sure he gets it from interpacific environmental (google "interpacific environemental" or interpacific.biz)

mrderf · July 2006

I Have just bought a 2005 Sierra with a 6.6 Duramax, (5-Speed allison Tranny). It Currently has 8000K on it and I am hauling a 10 000 Lb Trailer while on vacation. I just figured out my mileage and I am only getting 8.96 miles per Us Gallon. Am I expecting too much out of this expensive purchase? I really believed I would get at least 13 - 14 mpg. In litres it breaks down to 3.687 per Litre. I am wondering if the truck is working properly ???????

coontie57 · July 2006

It may be a little early to panic... the motor isn't broken in yet. I drove to AK last summer and talked to lots of folks with the Duramax and they were pulling big 5th wheels with multiple slides... they all reported 12-14 mpg... I just got a new one with now 1400 miles on it and next week I am taking my 10K 5th wheel out so perhaps I will know more ...

tdball · July 2006

I have a 2006 1 ton 4 WD crew cab LT loaded, leather, power everything, 6 CD Bose, etc. Bought it new in Sept '05 and now have 31,700 on it.

Fuel mileage varies with fuel, the cheaper #2 working best, and condition of the fuel filter. Number 1 fuel or auto diesel seems to cause rattles in the valves similar to a restricted fuel filter. The engine runs very smooth and quiet when all is well, but starts to sound a bit rattley when the fuel filter starts to get clogged. Mileage also suffers with a clogged filter. I keep a spare with me. I have used several different types of additives, but don't see a great deal of difference, if any. At present, Lucas fuel conditioner is the choice as an upper cylinder lube. When using the thinner fuels, a good conditioner like Lucas will quiet the rattles.

Mileage started slow, but increased at a steady pace. There were times when I was wondering if it would ever improve and get anywhere near 18.

Driving less than 70 MPH on cruise and flat ground gets me in the 20 MPG range. 55 MPH gets me 22-24 MPG; however, I seldom find long enough stretches of level, flat ground to take advantage of the economy. Traveling at 55 MPH is akin to watching paint dry, mileage or otherwise.

From northern Wyoming to West Texas at 70-95 for 1238 miles averaged 17.9

Head winds and tail winds make a lot of difference, as do long hills such as leaving Trinidad, CO. up over the pass into Raton, NM. Mileage suffers greatly with long hills at 75-85 MPH.

Town mileage varies, but is mostly poor at best, being between 14 and 17, but mostly in the 15-16 range.

Max speed is 95 and best cruise is 90 where possible, with a smooth, quiet, comfortable ride.

The biggest problem with the mileage, next to the exceptionally heavy right foot, that I have had is with the fuel filter. Theyre expensive, but so is a loss in MPG, so I change mine between 7,500 and 10,000 miles unless I suspect one is being restricted before that, but seldom go to 15,000. As a matter of fact, with almost 32k on the truck, I think Im on my 5th fuel filter. I wonder why, with the computer display showing the supposed oil and fuel filter life left, it doesnt sense the pressure differential and simply tell you to change the filter like it does with water in the fuel (I havent had water in the fuel, but its supposed to let you know if there is). Im not sure why the fuel clogs the filters so much, but Im glad they do, as that is better than a clogged injector nozzle. Baldwin filters are my first choice.

rseebo · July 2006

You may not see the 12 - 14 if you are towing a travel trailer. The 5th wheels are more economical while towing due to where they are located and the ability to use the draft of the vehicle a little better. I tow a 10k travel and see from 9 - 11 on average and typically am only doing 60 - 65 MPH. I now have 50K + miles on mine as well, so I know it is broken in.

coontie57 · July 2006

It sounds like a heavy foot is causing a heavy drain on your wallet too.

Actually what I wanted to ask was something I thought about a few days ago ... how does the truck KNOW when you change oil.... or fuel filter... Is it a mileage thing like someone told me... or a viscosity thing or something like that?

I am going to have to ask Chevy or something..

I got 18.8 on my first long trip of 250 miles or so.. and thats in the mtns from NC to VA and back.... but I didn't use the lead foot.. 60-65 and then 55 etc...

mrderf · July 2006

Thanks for the input. I too, am towing a travel trailer and while I am in Toronto Ont. I took it in for an oil change and the head diesel mechanic gave me a card to a high proformance friend of his and said the computer in the truck can be re-programmed. The meachanis I talked had the same done to his and reports a 25 - 35 % increase in mileage per tank. I am going to see the fella tomorrow and will post the results when I have them. AGAIN THANKS FOR YOUR INPUT.

fenceking · August 2006

I have an 05 6.6 Duramax 4X4 4 door 2500 HD @ 52K mileage. I was very happy because around town I was getting 16-18 mpg and here last month I took a trip 1K pulling a small boat and trailer and the best mpg on the trip was approx 10.5 and as low as 8 mpg. Since I returned home my fuel mileage has dropped to approx 12 - 13 mpg and I have taken it into the dealer and they tell me they can't find anything wrong. Before on trips with similar weight I have gotten as much as 20 mpg. I just can't understand what is going on!!

coontie57 · August 2006

Fenceking that sounds like a restriction in either the air filter/dirty or fuel filter/plugged. I pulled my large 20ft bass boat and got 13.1 in the mountains.. I don't know what it weighs but the 200 hp engine should tell you its heavy... two axles too.

KCRam · August 2006

I agree... reduced mileage with my Cummins is a sure sign that it's time to change the filters.

kcram - Pickups Host

bailey9r · August 2006

Amsoil says 5000 miles on all engines as a rule of thumb but it takes a bit more for a long lasting engine like a diesel. I would double that even though it is hard to wait but if you put it in too early it will never break in and you will have to put dino oil back in to finish breaking it in. I have been using amsoil for over 30 years and it has never let me down!

Ray

bailey9r · August 2006

when you reset your computer after changing your oil the computer starts counting revolutions of the engine (even at idle at a red light) then factors in throttle position and such to determine load so sometimes it will say change oil 2-3 thousand miles sooner or later than usual.

Ray

trucky1959 · August 2006

I have a 2003 2500HD, crew with 170,000 miles on it. I haul alot of weight, I have seen my milage run from 16 to 19. I have tried everything to remedy the problem. Bottom line is I feel that none of the fuel is consistsnt. I added the Juice Attitude, all that did was make me put my foot in it more..lol I still, hands down would never buy a gas burning truck again...Changing the fuel filter every 15,000 miles really makes no dif. I by mistake put 2 gallons of regular in my tank. The nozel was green like the diesel, it cost me 340.00 bucks before all was said and done. The fuel injectors run at 27,000 psi, and any loss of lubrication can damage the injectors. They not like the old engines where u used to put a little gas in your fuel to keep it from freezing.. GM recomended I have tank drained & filter replaced, it was covered under my comp. ins. If you have no deductable..

coontie57 · August 2006

Its interesting that I also had a Juice Attitude.. I could see that it did very little ... worsened the fuel mileage on my Ford 250 HD... diesel...just my estimate though

Thanks for the tip on the gas in the diesel tank... I still worry about doing that but now know its covered by the insurance.

C57

deerstrangler · August 2006

I HAVE A 2003 2500HD DURAMAX WITH THE ALLISON AUTO IN AN EX-CAB SHORT BED. I USUALLY JUST DRIVE IN TOWN WITH MY AVERAGE TRIP ONLY BEING 5 MILES AT A TIME. I AVERAGE 18-19 MPG WITH MY TRUCK AND THAT INFO COMES FROM ME DOING THE MATH NOT RELYING ON THE COMPUTER WHICH I HAVE FOUND TO BE LESS THAN ACCURATE. WHEN I GET OUT ON THE HIGHWAY I USUALLY GET 21 OR SO DEPENDING IF ITS REAL HIGHWAY DRIVING OR FAST TRAFFIC. WHEN I PUT MY 35' 5TH WHEEL BEHIND IS WHEN I LOSE MY MARBLES. I GET 10 OR SO GOING DOWN THE ROAD AND THAT IS WHAT STEAMS ME. THATS A LOT OF LOSS WHEN YOU PUT ON A LOAD. NEVER THE LESS I'VE DRIVEN FORDS AND DODGES AND THE DURAMAX WILL BE THE TRUCK IN MY DRIVEWAY UNTIL SOMEBODY MAKES AN IMPROVEMENT WORTH LOOKING INTO. NOT JUST AMPING UP HORSEPOWER AND TORQUE BUT KICKING THE ECONOMY UP A NOTCH OR TWO IS WHAT IM LOOKING FOR.

silverado9405 · August 2006

:confuse: hey i am currently a student at Nashville Auto Diesel College in Nashville, TN and i can tell you the reason for the cheaper fuel running better in your truck, DO NOT RUN THE MORE EXPENSIVE NUMBER ONE unless you want to change out your injects prematurely may also because causing your fuel filter problems do to problems with lubrication in the injects the NUMBER ONE FUEL IS A LOW SULFUR FUEL it does not have the lubricating properties as the #2 so unless you know for sure your engine is designed for low sulfur fuel DONT USE IT unless its worth the satisfaction of paying around 1500 to 2000 dollars for new injectors if you talk to someone at cat or detroit diesel they will tell you the same thing they have alot of trucks coming in for premature injector failure due to the low sulfar fuel it is a cleaner burning fuel thats why it is more expensive but no good for an engine not designed for it

pescador · August 2006

Check your fuel filter. Sounds to me it might need replacing.

clintflowers · September 2006

Anyone with any ideas: I got the "water in fuel" message today, but it drove OK long enough for me to get to an auto parts store. I bought plenty of water remover for diesels and put it in the tank. I drove home, left the truck running assuming it would process the cleanser by doing so, came back 5 minutes later, and it's dead.

Ideas on repair short of towing it to the dealer? She'll turn over but no hits.

Thanks,
Clint

oscar4 · September 2006

I just bought a new 2006 2500HD 4x4 crewcab Duramax with 106 miles on it. I am going to run B20 BioDiesel in it no number2 diesel. I will post here to let you Duramax dudes know how things are going.

All my research tell me this fuel with its extra lubricity will help diesel engines run smoother burn cleaner and free up any build up from using #2 for long periods of time. If you have been using #2 and switch to B20 you will have to change you fuel filters every other tank of fuel for about ten tanks because the biodiesel acts as a solvent and loosens the accumliated deposits in the fuel system and tank built up from the #2 diesel.

Here goes just bought my first tanks today and KNOX super stop in Dallas Texas.

KCRam · September 2006

"Water remover" usually doesn't do the job. If the fuel system detects water, you've got to drain it. Diesel is lighter than water, so the diesel will sit on top of the water in your fuel tank - pouring additive will thus not get to the water. But since the pump draws from the bottom of the tank, the water will get pulled to the engine first.

You also need to find the source of the water - either a leak, driving through a deep puddle, or bad fuel.

kcram - Pickups Host

stdbob · September 2006

You mention running #2 fuel instead of #1.
Is #2 the off road dyed diesel?
I'm hesitant to void my warranty.

gagrice · September 2006

Number one diesel is really kerosene. It will not gel at low temps. It is also used in jet aircraft. Commonly referred to as JetA fuel. It does not have the lubricating characteristics of number 2 diesel. We only used number 1 in our trucks in the Arctic, year round. I would say you are better off with number 2 diesel unless you have sustained temperatures of minus 20 degrees F for extended periods of time. Biodiesel gels at a higher temp than number 2 diesel. Most gas station in cold areas add a bit of number 1 in the winter to protect against gelling.

PS
most dyed diesel is number 2 used for tractors and off road use only. Big fines if you are caught with it in your on road vehicle.

spademan · October 2006

Has anybody upgraded their exhaust? What did you buy, and how has it performed??

mek0123 · October 2006

My brother has a 2004 Silverado LT 3500 with the Duramax Diesel that he ordered new with every available option and when he test drove two other Chevy 3500 model trucks prior to ordering his, the mirror control button would allow him to electronically fold in the trailer tow mirrors. He just recently realized after two years of ownership that his truck will not do this. GM nor the dealer has been of any assistance at all, after three calls/visits to each. Any idea why his won't work in this manner? Thanks and we both would appreciate any assistance at all.

wadegreene · October 2006

I just bought a 06 2500HD crew cab with the duramax/alison combo. I about spent all my retirement buying this truck and thought it would be a great replacement for my 1/2 ton and 1 ton. I love the truck but it gets the worst mileage out of all three! The first few tanks got 8-10 mpg and after a highway trip(unloaded) I still only get 13.8!!! Is there something wrong with this truck? If not, I think I wasted alot of money. Is there something I should make the dealer look at. Surely it must get better mpg than that.

pescador · October 2006

I have about 10K miles on my 2006. I am averaging around 13.8 also. SUCKS. Something has to be wrong, however Chevy simply says if it does not have an engine code, they have no where to go. Brain dead mechanics. My 2004 Duramax averaged 17 to 18 in the city and got 22 when I drove at 2000 RPM. My 2006 mileage drops when I drive 2000 RPM. Let me know if you find anything out.

wadegreene · October 2006

I just got off the phone with the dealer. They said they are researching what the mileage should be?? I could save them time. Do they think I didn't research all this info before I plopped down the 50K for the truck? My buddy's '04 gets 23mpg unloaded and 17-19 fully loaded. I have noticed that it is getting better with more and more tanks ran through it. I am praying that as it breaks in it will get better. I will keep you posted. After paying that much for a new truck, I will bug the dealer everyday until they give me another one if it doesn't improve.

coontie57 · October 2006

I bought the same truck in July... I get 11 mpg pulling my 11000 camper in the mtns... and I got 18.8 over 250 miles driving in the mountains of VA and NC back when it only had 500 miles on it. still only has 3500 on it

Are you sure you don't have the NON MPG rear end..??

Incidentally I pulled up Saluda Mtn I 26 today at 60mph.. shifted manually to 4th and had plenty of power left to accelerate if needed... My 250 Ford back in May could only do 31 - 32 mph... in 2nd and the engine at 2500 rpms or so.

Chevy Silverado and GMC Sierra Duramax Fuel Mileage

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