Mileage during break-in

Hogs · December 3, 2003

I just finished my first tank of gas in our 04 GMC Savana Cargo Van and I averaged 11mpg. It's a 2500 with the 6000 and 3.73's.

Our 02 Silverado extended cab 4X4 with the 5.3

and similar weight got close to 20 mpg.

Is there that much difference between the 6.0 and 5.3 as far as MPG or should I expect better mileage after break-in?

Thanks,

gunslinger45 · December 6, 2003

You can definitely expect better mileage after a certain amount of break in. The amount of mileage and the degree of better mpg will vary with every application, but in general you'll pick up maybe around 5% - 15% better mileage after sometime around 5 to 10K miles. Again, this is a rough range and depends on a lot of inidiviual factors. The main reason for this effect is all the seating and mating of bearings and gears that occur during the break in period. From the factory, things are tight, a little scewed from different torquing, and maybe slightly mis-mated. Its just a fact of manufacturing. As the engine and drivetrain operate over time, these imperfections are "smoothed out" and things begin to seat properly and many little inefficiencies are cleaned up and reduced. So yes, you will see better mileage, and power actually (though maybe not very noticeable) as the engine gets broken in. As a sidenote, this is why some people argue about not using synthetic oil until after a certain amount of miles to allow the engine to reach its "optimal" conditioning. Not arguing either way on this point right now, just wanted to bring it your attention as more evidence that the engine does change over time.

Gunslinger

gave20 · December 6, 2003

When I drive my truck around town avg. 38mph according to the DIC I get 13.4mpg ...When I drive the turnpike my avg. speed is 60mph according to the DIC but I cruise at 72 I get around 16mpg. I have 1200 miles on my engine so far and these numbers are very similar to others. It's just a gas hog

chevroletmb · December 7, 2003

a new truck will have less fuel milage until the computer learns fuel trim data.

the computer learn your driving style and sets itself up to run better.

the same thing will happen anytime the batter in disconnected for any length of time. good news it will get better

Hogs · December 7, 2003

Thanks guys!! If I end up getting 16 MPG I'll be very happy!!

Mike

422 SS · December 7, 2003

You can expect 14-15mpg under perfect conditions.I doubt you will get any better than that.I have a 3500 Express and it weighs 5900 lbs empty with me in it.I have 4.10's in my van and get between 11-13mpg in the 13,000 miles I've put on it.Fuel mileage always suffers in the colder months due to different fuel formulas.I don't believe you will see a 15% increase in mileage after break-in.Anything between 12-15mpg is normal for your new rig.I had a 99 with a 5.7 vortec that did'nt have the power the 6.0 has and the 6.0 gets about 3mpg better mileage.I think you will be very happy with your new purchase.

Hogs · December 7, 2003

You can expect 14-15mpg under perfect conditions.I doubt you will get any better than that.I have a 3500 Express and it weighs 5900 lbs empty with me in it.I have 4.10's in my van and get between 11-13mpg in the 13,000 miles I've put on it.Fuel mileage always suffers in the colder months due to different fuel formulas.I don't believe you will see a 15% increase in mileage after break-in.Anything between 12-15mpg is normal for your new rig.I had a 99 with a 5.7 vortec that did'nt have the power the 6.0 has and the 6.0 gets about 3mpg better mileage.I think you will be very happy with your new purchase.

I'm already very pleased with it. I had just bought an 02 Dodge Ram 1500 Van and it was a true POS and was almost uncontrollable towing a 2500lb utility trailer. It had the 318 and got 13 mpg with only 225 HP

This new Van f-in get's it!!!