2009 Chevy 3500 6.0l with bad fuel mileage

[Valv]

At the shop we have a brand new 2009 Chevy 3500, 4x4, long box, single cab, dually, with the 6.0l, 6 speed auto, 3:73 gear ratio.

Truck now has 9000 miles and since new it does 5.5mpg/7.5mpg towing (RVs, trailers, etc), and 12mpg empty.

Local mechanic checked O2 readings and found it normal.

I wanted to wait until well broke in to start complaining, and now at over 9000 miles I am really concerned. We have 454s with 150k miles that do 10mpg towing and 14mpg empty, this new one is real "killer".

Anybody has more or less same truck configuration and had better mileage ?

[coonchaser]

Thats a 6.0 awesome engine bad on gas lol...i had a four door crew cab 3/4 ton, no duals but it got 12mpg no matter what i did, i never checked it towing but it never got better than 12 i know that

[Jungda99]

That is what the 6.0L does. tons of power but 13MPG towing or not (pretty much)

My dad had the 6.0L with 4:10s and 13MPG was the highest he ever got!

[Dave S]

My old Ford Ranger with the 4.0L V6 got 3 mpg towing a boat 35 miles. The boat was a 16 ft Sylvan Backtroller. On the flip side, I could put a Polaris Sportsman 500 in the back and get 20 mpg. Strangest thing I've ever seen. Dealership was no help.

To eliminate any chance of my own embarassment, I even stopped to check if the hubs on the boat trailer were seized up or if the parking brake was on. Nothing!!!!

[jeffreyd]

how about putting a cold air intake on it to start. i did a simple swap of filter only to an airraid filter on my hemi and it added 3 mpg. you could always look at putting in a chip, if you want to go to that extreme. also if you open up the exhaust that will help but you have a new truck and would expect it to do much much better than what you are seeing. really sucks that todays mfg is still allowed to get away with this stuff, knowing that it wont make the sticker as when the set those mpgs they are in a perfect world. time that the consumer starts raising heck about the [PoorWordUsage] that is put on us. contact the consumer compliance folks at the federal level and let them figure it out if you have the patience. good luck

[Whoaru99]

Wow. +3mpg by changing the air filter/intake? If we're talking 12-14mpg to start and add 3, that's a HUGE increase..like 20-25%. Almost seems too good to be true. If the intake system was that restrictive, and that easy to fis, it's hard to imagine the OEM wouldn't open it up to increase their mileage specs.

In a lot of cases, gas mileage hasn't gone up that much on trucks...but look at how the HP numbers have gone up. Hard to make power without fuel.

[LMITOUT]

A few years ago when the 8.1L was available many people were saying that it was better to just go for that engine instead of the 6.0L because it had more power for almost the same mileage as the 6.0L.

I had a 6.0L. 12-14mpg was all that it would get.....and the 14 was with a tailwind...a stiff tailwind.

No sense complaining or taking it to the dealer unless you plan on trading it off. I'm just glad I got rid of it before gas prices shot up as they have in the past few years.

[Hafnutz]

I can't imagine there is much if anything you can do. All these "miracle cures" you read about probably don't really do anything or may even make it worse. The Manufactures are trying to squeeze as much mileage out of them as they can to make their product more competitive. If was as easy a different air filter or air box design wouldn't you think they'd have already done that?

[jeffreyd]

3 mpg is correct, i did not believe it either. my boss gave me the filter as he went with a k&n. I simply put it in, did my normal service and filled up. checked the mileage as i normally did and it did a great increase. i normally would get around 15 on my dodge 44 3/4 ton with the hemi. even today i still see 18 or a tad higher as i drive. naturally keeping my foot out of it helps but was not that big of a deal. even if it only got 1 mile, that is a ton of cash over time.

[Dozer]

I agree with Hafnuts. If there was something so simple that would make such an improvement dont you think they would do that at the factory?

[jeffreyd]

well for less than 50 bucks in most cases you can find out yourself. replace the oem filter and put the air raid in, when you feel it is time to clean take it out and run thru dishwasher. everyone is pointing at the fact that i have gained mileage but that is not a reason for any mfg to allow a vehicle to come off the line that does not get 18+ mpg. If we are buying into the 12 mpg arena we might as well buy a tractor trailer and use that. heck the new 18 wheelers are getting up to 10 mpg. big increase from years past, where your 6.0 is at. the other thing is to see that you did not get a california vehicle. they have other equipment installed to lower the emissions. this will only get worse in the next couple years as emissions levels will change again. so with this in mind, i will run my hemi with my air raid and get my 18 mpg. wont change to a paper filter unless i am cleaning the other one and need to use my truck for something.

I also look at this like i look at synthetic oils. we all know how well they work but the factory will not fill or even recommend them. So knowing that if i change to amsoil and do the extended drain, that too might increase my mpg a tad. So i guess that if i do this conversion, it too is too easy and the factory should have thought of it first? Oh well i will do it all and be happy.

[Whoaru99]

I also look at this like i look at synthetic oils. we all know how well they work but the factory will not fill or even recommend them. So knowing that if i change to amsoil and do the extended drain, that too might increase my mpg a tad. So i guess that if i do this conversion, it too is too easy and the factory should have thought of it first? Oh well i will do it all and be happy.

I use synthetics too. But, as I work for an OEM where engines and expensive hyraulics are involved, promoting extended drain intervals is a risky proposition. Some percentage of the population has trouble with the typical maintenance and service recommendations during the 3,000 miles or what ever it is now. How many of the typical population might run their vehicle out of oil or forget to have it changed at all if the change intervals were 20 or 25K miles?

Believe me, if we could stroke 20% fuel economy improvement by merely changing a $50 air filter, we'd be all over it yesterday!!!

I have no way to verify your claim, nor is my intent to discredit it. But, as the old addage goes, when something seems too good to be true...ask more questions.

[duckhunter889900]

Put a Cold Air Intake on they really work!!! I put the K&N in and honestly get 2-3 mpg better than i was. And you can always put a throttle body spacer in they will give you an extra 1-2 mpg. Just my 2 cents

[jeffreyd]

Whoaru i appreciate your comments and agree, one can only ask questions. But as you can see below your post is someone talking about putting in a spacer and changing to the k&n. Going back to my original comment, i got this filter from my boss. He did the whole change over, new box, spacer, and chip. the issue he ran into was that on the air intake box, you have to put a resistor in the circuit to fake out the computer. So he went back with the oem air intake and did a different filter. He not only increased hp but did a tremendous jump on the mileage. I can only go by my changes and sharing them is truly a matter of opinion.

I a a firm believer in syn oils. I can relate to your thought about some folks would not change old non detergent oil at 3k let alone tell them now you can go 24k. it would be a pan full of crud. we did convert our police cars to amsoil and went with 7500 mile change. the cars would still come in at 3200 for inspection and oil sample. by the time the sample came back, the car would be close for pm again and we would decide then to change or run one more time. most times however it was so close that we would drop the oil and filter.

I think if a person wanted to try some fairly cheap methods before putting in a chip or spacer, a cold air filter would help. might surprise some of the nay sayers too. great conversation, thanks

[fishorgolf]

What type of tires are you running on the truck? I have a 6.0 in my Yukon XL and with the factory VERY hard road tires I would get 15/16 miles to the gallon. (would get stuck in 3" snow) I switched over to some softer aggressive tires and that dropped to 13.5. This of course is without a load which lowers my milage by aprox. 3-3.5 mpg.

[fishin58]

Some of you are are comparing apple and oranges with the old GM 6.0L and the new body 07 and newer would have a improved 6.0 liter a more high performance engine comparable to what the Denali had for most of the 2000's. The newer HD 6.0 does have an increase in gas mileage and power.

[deadeye]

Thats what happens when you try to move a 1 ton with a small block. Its a great motor, don't get me wrong, its just too much for it to handle efficiently. It may still get up and go ok, but its still not working efficiently. You can do what you want to it, but its still not going to do a whole lot better.

[Valv]

Thats what happens when you try to move a 1 ton with a small block. Its a great motor, don't get me wrong, its just too much for it to handle efficiently. It may still get up and go ok, but its still not working efficiently. You can do what you want to it, but its still not going to do a whole lot better.

I agree there, the only issue I have is that the older 6.0 has better mileage and tows just fine, especially if you get a 4:10. It's the new one that is a "killer".

We have the 6 speed auto, when towing it will never get out of 4th gear, usually howls in 3rd then go to 4th, 5th and 6th are never used unless we're going downhill.

[MN Mike]

At the shop we have a brand new 2009 Chevy 3500, 4x4, long box, single cab, dually, with the 6.0l, 6 speed auto, 3:73 gear ratio.

Truck now has 9000 miles and since new it does 5.5mpg/7.5mpg towing (RVs, trailers, etc), and 12mpg empty.

When we run out west snowmobiling, thats pretty much our average gas mileage towing too, 3/4 ton

Chevs with the 6.0, '09 1/2 ton Dodge with the HEMI and a '09 GMC All Terrain with the 6.0. We run around 75 mph plus with a 4 place sled trailer, 4 guys and all the gear.

You mentioned the 454, we blew out a rear end in Beach ND a few years back, it was a 97 GMC vortec 5.7 ( if I remember right ) ended up renting a 99 Suburban with a 454, we went from 5 mpg with the 5.7 to over 12 mpg with the 454, the gas we saved paid for the rental of the Sub. that 454 motored thru those mountains like nobodys business.

Not much you'll be able to do with the mpg on the dually but empty I would think you could get better depending on the speed your driving.

Mike

[deadeye]

They just tried to squeeze too much out of it. You need torque not horsepower for that kind of hauling. That newer 6.0 motor rocks in the cars but its just not made for trucks now. The powerband is in the wrong place in the rpm range for towing. Drop a older big block (the 8.1) in its place and you would be mint.

I hate to say it, but it may be worth "upgrading" to a older truck.