GM 5.3 vs. 6.0 mileage?

TX48 · May 10, 2008

I have had my gm 2500 07 (new body style) with the 6.0 6 speed with a 373 R.E. since Oct. with 14000 miles now I have just hit 17 mpg at 65 mph hwy and some city driving. It got 14 off the lot. Pulling a 2 horse or my 20ft flatbed trailer its around 9-10 depending if I use trailer mode. This truck has tons of power. I was a ford guy but their engines are gutless (gas). If you are thinking about this truck you will not be disapointed. Later John

Dargo · May 10, 2008

Builder said:
I agree. Now GM has no big block gas competition for the Ford V-10. I heard the 8.1L had owners complaining about knocking from the engine compartment.

I have a GM 8.2 and 9.4 big block, but they don't get very good fuel economy.

My dad thinks I'm a traitor for buying anything Ford, but I do have to admit that the 6.8 V10 Ford pulls better and still gets the same or better mpg than the GM 6.0 I had. I still think a gasser has it's place for towing under 14 or 15k. Anything over that and I personally haven't driven any gasser that pulls like my diesels. But, since we're talking mpg, it's relatively common for the Ford 6.8 V10 to get 17 on the highway and that's about the best I ever got under similar conditions with a 6.0 GM.

dixie306 · May 10, 2008

asylum575 said:
I have a 3/4 ton with the 6.0 and 4 spd automatic. 2006 model year. I get between 10-12MPG. In 2007 they added a new 6 spd, not allison to the 6.0. Should do a little better. The 5.3 does much better. The 6.o is the best gas tower GM makes, they got rid of the 8.1/allison combo. Nobody is looking at diesels these days. Big upfront cost and more at the pump.

I had a GMC 1500HD with the 6.0 mileage was 11.8 with it, beautiful truck, rode like a cadilliac and would pass anything except a gas station. I have a GMC 1500 now with the 5.3 and its doing around 18 a gallon around town. I tow a light weight fifth wheel with it and while it doesn't have the power the 6.0 does, the 5.3 is doing better than I expected it would with the fiver.

asylum575 · May 10, 2008

Dixie,
I have the 1500HD also. Love the ride and power, but your right. It can pass anything except a gas station. Probably will go for a 5.3 or wait for the 6.0 Hybrid for the 2009 model year.

FlaDon · May 10, 2008

Builder said:
I agree. Now GM has no big block gas competition for the Ford V-10. I heard the 8.1L had owners complaining about knocking from the engine compartment.

Never heard any from mine. The lifters take a little bit to charge but that is normal. And passengers do sometimes ask about the whine the tranny makes.

Yes it is normal. Yes it has done it since day one. I tell them that it's because it is a "true" truck tranny. You hear it in the 8.1 where you don't in the Duramax because the 8.1 is a quieter running engine. Unless you're behind my tailpipe.

Builder · May 11, 2008

Dargo said:
I have a GM 8.2 and 9.4 big block, but they don't get very good fuel economy. My dad thinks I'm a traitor for buying anything Ford, but I do have to admit that the 6.8 V10 Ford pulls better and still gets the same or better mpg than the GM 6.0 I had. I still think a gasser has it's place for towing under 14 or 15k. Anything over that and I personally haven't driven any gasser that pulls like my diesels. But, since we're talking mpg, it's relatively common for the Ford 6.8 V10 to get 17 on the highway and that's about the best I ever got under similar conditions with a 6.0 GM.

I don't think the 6.0 GM was ever meant to be competition in towing for the Ford V-10, it was meant to be competition for the Ford 5.4L V-8 where it does real well. The GM 8.1L was meant to compete against the V-10. The new GM 6.2L will definately fill the big block void GM has had for a few years now with much less displacement than the 8.1L.

I think what GM tried to do 2-3 years ago was steer big block gas buyers into the duramax by dropping its' big block 8.1L gasser. That's when diesel was $2-3/gallon

Unfortunately, with these ridiculous diesel prices, that little experiment failed.

That's why big block gas is coming back in 3 months.

dixie306 · May 11, 2008

asylum575 said:
Dixie,
I have the 1500HD also. Love the ride and power, but your right. It can pass anything except a gas station. Probably will go for a 5.3 or wait for the 6.0 Hybrid for the 2009 model year.

I'm about to get WAY off topic here, but I have to ask, as anyone here tried or know of anyone whose tried a HHO "injection" system, I kind of poo-pooed the idea until I found out both Honda and GM are introducing cars that use a hydrogen fuel cell in the near future.

KAB · May 11, 2008

Builder said:
I think what GM tried to do 2-3 years ago was steer big block gas buyers into the duramax by dropping its' big block 8.1L gasser. That's when diesel was $2-3/gallon

That's why big block gas is coming back in 3 months.

Actually the drop of the 8.1 was supposedly due to emission issues. It is still availble in the 4500/5500 series.

The 6.2 is a small block.

Kurt

Builder · May 11, 2008

KAB said:
Actually the drop of the 8.1 was supposedly due to emission issues. It is still availble in the 4500/5500 series.

The 6.2 is a small block.

Kurt

I don't think it was due to emmissions.

I know the 6.2 is a "small block", but it's made to compete with big blocks from the competition.