I'm shopping for a new truck and considering the 6.0. I currently have a 02 6.0, which knocks of course, but has caused me no troubles. Is the NEW 6.0 "04-05" improved over the earlier 99--02 design? no knock? smoother? fuel economy any better? any other benefits???
Thanks,

My 2002 didn't knock so I can't compare. My 2004 is just as quiet and smooth as my 2002. Only difference I can think of is that the 2004's have a drive by wire system as opposed to a throttle cable...

The 6.0L gas motor is the same as when it was 1st introduced in 1999.

sure the motor is basically the same design but they have obviously changed stuff and improved it.

to answer your question, only the 99-02s had the knock problem, 03-05s dont. fuel economy is obviously better because folks on here that had the earlier models complain about 10-12 mpg numbers, now you can expect 13-15 out of the newer models. as far as power numbers, im not sure what the earlier ones had or if they increased in the newer models. i have been very happy with mine thus far.

One thing I find interesting is that the 5.3L has had two bumps up in horsepower since 1999, from 270hp to 285hp, and now at 295hp. The 6.0L is still rated the same for 6 years running, at 300hp.

I wish my 04 would get 13-15 mpg. I get 11-12 tops.

The later models will not exceed the earlier models as far as fuel economy goes.

to answer your question, only the 99-02s had the knock problem, 03-05s dont.
Thats weird, My 2004 6.0 Knocks like it has a rod knock. GM says its normal.
Normal my butt.

Thanks for all the reply's, It sounds like GM has improved the engine verses the original version. I don't know if it's related but my 02 eng doesn't seem to have near the power of when it was new, how's the 03-05's with improved design, is the power staying with the engine longer??? I'm up in MN burning corn gas, getting 10-12, if I was in an area that didn't use ogygenated fuels, it would probably be 13-15... I was hoping someone from MN would tell me otherwise...

My 04 will get 14 on the highway and 12 intown with mid grade gas.
I have a K&N airfilter and a Leer topper on it. This is ND driving so
there is always a breeze blowing somewhere. The best I ever got was
when it was brand new 16 on the highway.

Hookem,

I owned a 01 xcab 8600GVW and an 03 Ccab 9200GVW 6.0. The 03 was smoother and quieter with no knock like the 01. Both got a top of 14mpg, even though the 03 was heavier. The 03 felt like it had more power, which I believe was due to different PCM programming from the factory.

I don't know if any of you have ever looked, but one thing that I have seen in looking around is that on the hypertech website, they have dyno numbers of the 6.0 and of the 5.3. Apparently the 5.3(year 2000) without the hypertech dynoed at an ADDITIONAL 28hp and 27lb-ft of torque over the stock 6.0. But, i am very skeptical of this data since all of the 6.0s which they have dyno charts listed for have the same hp and torque(they have like 3 or 4 different model years listed with charts) both before and after the hypertech. Anyway, take it how you will, but i found this rather interesting.

Had a '97 extended cab long box 2500 with the defunct 5.7 and a 3.73 in the fanny. The truck towed (5,000 lb) very well and got 15 mpg doing so. 17 to 18 mpg on the road no tow and 2,000 lb load. 14 to 15 in town. Don't know why GM did away with this and went to 6.0 as a standard engine. It was a great application for almost every purpose except very heavy towing.

They have coated pistons now (to try to hide the knocking).. at least thats the only thing I noticed when they rebuilt mine last spring.. 30,000 later it sounds like the d-max at idle. 14.87 mpg back roads and town. BTW they have been rated at 300 hp sence 99

dcraig,
Your 6.0 is getting almost 15mpg on back roads? What do you get highway then? I'm most likely going to be buying a 6.0 in the summer and am trying to find out as much as I can. I test drove a 6.0 and the sales guy said 18 on the highway, it took everything in me to not laugh. Thanks

im glad to hear you dont believe the salesman. one salesman was trying to sell me on the 8.1 and i told him i couldnt afford the gas. he told me that neither an 8.1 or 6.0 would get above 10mpg and that he owned a 1500 z71 with the 5.3 and it never got over 12. i told him he had something wrong b/c i know for a fact the 5.3 gets well above that. the majority of salesmen are freaking idiots. and liars.

I've had them all. These are realistic mpg that you will see on the highway.
5.3L 17mpg
6.0L 14mpg
8.1L 11mpg
All trucks were extended cab short box's with 3.73 axle ratios.

They have coated pistons now (to try to hide the knocking).. at least thats the only thing I noticed when they rebuilt mine last spring.. 30,000 later it sounds like the d-max at idle. 14.87 mpg back roads and town. BTW they have been rated at 300 hp sence 99
May I ask why they had to reubuild your motor? Also, how many miles where on it?

William

Well only time im on the highway with it is towing normaly a 3 horse bumper pull, it gets about 11-12 doing that at 70

They rebuilt it becaus it sounded like someone was under it knocking on the hood with a hammer at idle, and I was getting ready to buy the d-max and said there was no way i was buying a gm if they didnt take care of me on the one I had it had 70,000 on it at the time, but had to bring up the words sue, Attorney, and Local Paper... 105,00 now and back to the knocking...

I us to have a 99 Silverado 2500 with the 6.0 and 4.10 gears. Never got over 12 mpg driving to work. Half city and half highway driving. Didn't really knock that bad except when it was first started up.

Mine has 3.73

I've had them all. These are realistic mpg that you will see on the highway.
5.3L 17mpg
6.0L 14mpg
8.1L 11mpg
All trucks were extended cab short box's with 3.73 axle ratios.

Those numbers are just about dead nuts with mine.

'02 5.3 Tahoe 3.42:1 16-17mpg
'00 6.0 2500 sc/lb 3.73:1 13-14mpg
'03 8.1 2500HD sc/lb 3.73:1 10-11mpg

Thats why I'm drivin' the Diesel now... except the wife's Tahoe. Waiting for the new '06 Tahoe redesign for her.

my 6.0 always gets 13 mpg highwaycity even at a stand still it just always gets 13. i wouldnt mind the millage if maybe there was some power behind it. makes me wish the denali came with an 8.1 or even better a dmax. i wish they still had the 5.7 what a great engine

I cant afford to fill my tank to get a good milage reading. I figured that when towing my 8k lb camper i was getting about 5 mpg. That still seems low might be as high a 7 mpg. Seem severytime I take my truck on the interstate, I am fighting a head wind of atleast 20 mph both directions. Sucks to be me.

FTR: My 6.0 still has just about the same engine slap it had new. I can get 16s on a straight highway trip, doing 65-73 MPH. Around town and to work(which is mostly highway) I generally run 12.5, and that is almost always the number. I check it often.


braz
2002 4x4 1500HD 52K 3.73

I just barely bought a 2004 2500HD Crew Cab 4x4 Silverado with 4.10 gears and the 6.0 liter Vortec. When I took it up the rocky mountain interstate hills at over 80 mph it got 14.5 miles per gallon with just about 1000 pounds of people and luggage. However, on the next leg of the same trip through similar mountain interstate hills I took it up the hills at barely 75mph and got 18.4 mph! Sounds like I got a good one.

I would love to know how you guys are getting 18mpg, theres is no way unless your following a big rig!As for the 6.0 knock, mine sounds like drum solo in the morning, I really don't care becasue it runs great, but damn is it loud. I just keep beating the snot out of it and its been doing this for 60k. Not an issue but some people get real worried when a motor makes that much noise. Its real loud!

My 03 1500HD gets about 14-15mpg in the city and about 16-17mpg hwy it has 3.73s most of them had 4.10s:eek: , 3.42s would have been nice or a taller OD. Engine knock is not really a problem, only when its cold its a little loud, from inside the truck you cant hear it.

'04 dmax 19 mpg 3.73 (sold)
'98 Z71 5.7 18mpg 3.73 (traded for Dmax)
'99 Z71 4.8 17mpg 4.10 (currently own)

These are best case highway miles. PS the 255hp 5.7 runs circles around the 275hp 4.8. And the Dmax was just plain awsome.

My 93 5.7L( throttle body) got 16-17 highway, why would a 6.0l with better a
better inj system get less millage???? Is this progress? Does .3 liters make that much diff...

The injection system on the new motors is more advanced, but you're also going from 200hp to 300hp in the process.

My 03 1500HD gets about 14-15mpg in the city and about 16-17mpg hwy

That would be awesome. I have the '03 1500HD and I get about 14 on the highway and between 10.5 and 12 in the city. I didn't notice any change when I put 285's on either. It has the 4.10's. I wish now that I had the 3.73. That would help quite a bit. My '00 1500 with the 5.3 got about 16-19 hwy and 14-16 city.

Thats weird, My 2004 6.0 Knocks like it has a rod knock. GM says its normal.
Normal my butt.

Its Nothing Wrong With The Knocking, It Might Sound Bad But Its Nothing Trust Me Ive Worked On Them, And Tore Down The Engines That Had Been Knocking, It Was A Wrecked 1999 Chevrolet Silverado 5.3L 270Hp V8, And The Cylinder Walls Were IN Great Shape Considering The Truck Had 142K On The Odmeter.

I Thought It Was A Problem Too When It Was First Discoverd, But I Prooved Myself Wrong.

I don't know if any of you have ever looked, but one thing that I have seen in looking around is that on the hypertech website, they have dyno numbers of the 6.0 and of the 5.3. Apparently the 5.3(year 2000) without the hypertech dynoed at an ADDITIONAL 28hp and 27lb-ft of torque over the stock 6.0. But, i am very skeptical of this data since all of the 6.0s which they have dyno charts listed for have the same hp and torque(they have like 3 or 4 different model years listed with charts) both before and after the hypertech. Anyway, take it how you will, but i found this rather interesting.

That Reasoning Is Bc The 6.0L Has Alittle Bigger Everything To Turn: Transmission, Driveshaft, And Rear End. Which Equals Loss In Power