[Jim Zeek]

I'm looking at used trucks. what are the fuel mileages with the 5.3 and the 6.0. found a real nice 2001 2500hd Silverado with the 6.0. this would be 4x4 trucks. thanks

[ron cozzo]

I have a 2002 Sierra Denali with 6.0, 4:10 gears and full time AWD. I think my lifetime economy is around 13. Gets around 8 pulling an enclosed trailer. Without the AWD a friend got about 2mpg better on the highway towing. Just highway driving, just under 20 is possible for me.

[lfdsteve]

2002 Tahoe 5.3 l
200000 miles +- And been averaging 13 mpg since new.
Steve

[steve v]

My 2004 2500HD ext cab, 6.0 w/4:10 gears gets 13-14 empty on the highway. About 10 pulling an open car trailer loaded, 8 pulling a 24' enclosed trailer loaded.

[DOC]

2006 Silverado Crew cab 2500 4x4, 3.73 gears. Duramax diesel. Cold air intake and 4' exhaust. 19-21mpg empty on the interstate at 65-70mph. 16 MPG w/ flat 18' trailer with 4 ATV's. 11-13mpg w/ 24' enclosed trailer loaded. I know it's not the gas motor but something to think about. I traded my 5.3 in because it worked pretty hard to pull the 4 ATV's at interstate speeds and I did not want to destroy the engine/trans/ so went with the diesel and have not looked back. would rather have the durabilty and pay extra for the gas.

[Jim Zeek]

Originally Posted by DOC

2006 Silverado Crew cab 2500 4x4, 3.73 gears. Duramax diesel. Cold air intake and 4' exhaust. 19-21mpg empty on the interstate at 65-70mph. 16 MPG w/ flat 18' trailer with 4 ATV's. 11-13mpg w/ 24' enclosed trailer loaded. I know it's not the gas motor but something to think about. I traded my 5.3 in because it worked pretty hard to pull the 4 ATV's at interstate speeds and I did not want to destroy the engine/trans/ so went with the diesel and have not looked back. would rather have the durabilty and pay extra for the gas.

i already have a 2012 denali hd with the duramax (had a 2007.5 3500hd with duramax before that). this will be a work/everyday vehicle. I'd love another duramax but they are commanding high prices. all used trucks are way high. I'm seeing stuff with 200k on them for $7000.00. really only want to spend about 3k on a work vehicle but they are all junk. just want to compare big trucks vs s-10s with 4.3's

[Deadhead]

Owned many 5.3 Yukon XLs with 3.73 and one '01 Sierra 2500 HD with 4.10 and 6.0. All 4wd none with the AWD.

I could get 19 on the Hwy in the Yukons at 75. I recently got 15 with my Sierra on a long trip with a complete rear end and some other parts in the bed, but prior to that it was always 12-13.

There are some valve train issues with the '01 6.0s

[67drake]

My 99' 2500 with the 6.0 got 16 MPG rural driving. It had 3.73's.

[mechanic17]

I hear you--I bought my Sierra 5.3 4wd in '09 new because used truck prices were ridiculous.

I too would like a diesel, but that payment ain't about to happen.

Mine has the Active Fuel Management and will do the claimed 20mpg highway on a trip, but mixed commuting is like 15, and towing 6000lbs gets 10-11. This is still with the old 4-speed tranny.

I am actually looking at getting into an old truck with no computers, like a '70-72 C10. I'm afraid of what the next failed sensor or black box is going to cost me. Been happy with the truck, but I think the total cost of ownership over the planned 20 years will be too high. Remember that when thinking about sacrificing a couple mpgs: Reliability.

[77 Canamman]

Originally Posted by mechanic17

I hear you--I bought my Sierra 5.3 4wd in '09 new because used truck prices were ridiculous.



Mine has the Active Fuel Management and will do the claimed 20mpg highway on a trip, but mixed commuting is like 15, and towing 6000lbs gets 10-11. This is still with the old 4-speed tranny.

I am actually looking at getting into an old truck with no computers, like a '70-72 C10. I'm afraid of what the next failed sensor or black box is going to cost me. Been happy with the truck, but I think the total cost of ownership over the planned 20 years will be too high. Remember that when thinking about sacrificing a couple mpgs: Reliability.

The AFM is trouble, pure and simple. I have a 2013 Sierra with the 5.3, and at 1500 miles, I bought a Diablosport Intune, and got rid of the annoying AFM, and have not experienced any loss of MPG. I have a V8 all of the time, which is exactly what I want from it! In good weather, I have averaged over 16 MPG. Right now with the remote starting and cold weather, just below 15MPG average, and I drive in hilly territory.

I bought this truck a few months ago for under $29k. It stickered for $40k.

[Deadhead]

Story on '07. We had an '07 5.3 XL and planned on keeping it forever. Liked the truck a lot. Well, in '11 after putting over 100k on it, began using some oil. I was changing plugs and noticed that there was oil in 4-5 holes. Ran Mob. 1 in it from new and changed on religious schedule. Buh bye. That had the AFM on it and would only get max 15-16 MPG. If I am not mistaken, they went to all electric fans etc. on that truck too, and it still got WORSE mileage than the '01 & '02 versions we had that IIRC had mechanical fans and non AFM engines for sure. Identical driving conditions. WTF? '01-02 were good years for these trucks.

[68gtoMN]

Will get poor mileage. Do not purchase if that's a concern.

[David Holmberg]

Speed kills!

Anything above 60 is eating more fuel. The 6.0 can get 18 if you drive like an old woman, but who has time for that.

Doesn't matter what gearing or transmission you have, as speed goes up the aerodynamic forces will hurt your MPG.

[77 Canamman]

Originally Posted by Deadhead

Story on '07. We had an '07 5.3 XL and planned on keeping it forever. Liked the truck a lot. Well, in '11 after putting over 100k on it, began using some oil. I was changing plugs and noticed that there was oil in 4-5 holes. Ran Mob. 1 in it from new and changed on religious schedule. Buh bye. That had the AFM on it and would only get max 15-16 MPG. If I am not mistaken, they went to all electric fans etc. on that truck too, and it still got WORSE mileage than the '01 & '02 versions we had that IIRC had mechanical fans and non AFM engines for sure. Identical driving conditions. WTF? '01-02 were good years for these trucks.

There were a lot of revisions done to the AFM 5.3 in 2010 that has corrected the oil usage issue that was fairly common on the 2007-2009 trucks. Mine has gotten 20 MPG on trips, but the city driving kills the average mileage on a heavy truck. Since I have bought it, the few modifications I have done to it have really increased the power. I am very happy with it.

[chrisinestes]

'99 GMC 1500 4x4 5.3L 3.73s 225k miles.

It lives at 7500 ft. 85 octane fuel. I get 16ish city and 21ish Highway empty.

Chris

[sdbob]

My 2wd 2005 had 5.3 4psd auto-3:73's got about 16 average.Extend cab 8' bed with cap.Actually from checking mpg. towing from Latrobe to Norwalk twice with the 05 then my 11(same except 3:08's and 6spd) the 05 seemed more powerful and better alround mpg at least for our hills in W-Pa.

[steve v]

Jim, Something else to look out for on this vintage of GM trucks is rusted out brake/ fuel lines. Even living in the Southern States doesn't help, I was surprised to see how rusted the brake & fuel lines on my truck were even though we're not in the snow/salt/rust belt down here. The puddle of brake fluid on my driveway tells me I'll be ordering up the "new" line kit they have this week.

[ron cozzo]

Been there, done that. The brake lines on my '02 rusted out at 70K mi, 10 years old. Junk metal.

[Region Warrior]

For some reason 6.0's don't get near as good as 5.3's.
Guys here say they avg 11-12 with 6.0's(13-14 on a good day). 5.3's 16-18.

My 99 K1500 5.3 with 3.73's, heavy cap and 60-70 lbs in 6.5 bed, 1/2 worn GY Wranglers gets 16-18 avg back and forth to work.
Don't push it hard cause cant beat traffic and lights anyway(14 miles @ 55-60 mph, 12-14 lights depending on route).
Just this Thanksgiving, got 22-23 on highway(60-65 mph, some 70) to KY(5.5 hrs) and back w/4 adults and 1 child, and bed packed full of cloths, food, etc.
When pull'n 3450lb car on open trailer, bed full, 3 adults to Norwalk @ 65-70 mph, get same 22-23. But again, don't hurry cause it's a 5 hr drive.

[Region Warrior]

The rear brake line went on mine at 90K.
I just cut out as much as could and made/rerouted a new line w/o drop'n fuel tank.
Hardest part was get'n at the top/front of the control module w/a 90 degree bend.
Found out after GM has a service bulletin on 99-02's. All 5 lines in a kit pre bent for only $110 retail.
Had known that would of got that even though fronts still look fine.