# 2001 2500hd 8.1 liter



## Scenic Lawnscape (Sep 19, 2003)

what are the pros and cons of this truck? 4x4 crew cab


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## erkoehler (Sep 25, 2008)

Just picked up the same truck except I got the 6.0L gas engine. Hopefully I'll be able to put it to work in the next week!


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## Rc2505 (Feb 5, 2007)

I know one of the cons. At least with my 1999 2500 crew cab. It takes about 40 acres to turn the damn thing around. A standard 3 point turn in most trucks = a 6 point turn in my truck. Add the plow, and the spreader on the back and it's almost 25 feet long.


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## ChevKid03 (Dec 23, 2007)

i heard from rumor that they tend to use a bit of oil in between oil changes....


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## Mark13 (Dec 3, 2006)

Find B&B, he's got a beast of his own and will tell you anything you'd like to know.

Pros- allison 1000 trans, aam 11.5 rear axle, hauls major tail

Cons- Thirsty


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## mercer_me (Sep 13, 2008)

A freind of mine has one with the 8.1 and it gets horible gas milage, alot worse than the 6.0.


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## Onebadbowtie86 (Oct 21, 2008)

I didnt know gas mileage could get any worse then the 6.0? my 2003 2500hd with the 6.0 and 4.10's averaged around 10-12, what does a 8.1 get?


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## Mark13 (Dec 3, 2006)

Onebadbowtie86;653972 said:


> I didnt know gas mileage could get any worse then the 6.0? my 2003 2500hd with the 6.0 and 4.10's averaged around 10-12, what does a 8.1 get?


I think around town 9-10 and hwy- 11-14. I've heard a pcm tune, full exhaust (headers all the way back) will really help them out.


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## B&B (Nov 4, 2006)

Mark13;653319 said:


> Find B&B, he's got a beast of his own and will tell you anything you'd like to know.
> 
> Pros- Allison 1000 trans, aam 11.5 rear axle, hauls major tail.
> 
> Cons- Thirsty


Mark pretty much has it covered.

Since the one in question is a first year truck the main things you want to check is if its had all the TSB updates done on it for the drivetrain. This includes the revised intake bolts (lessens oil consumption), the drain back valve in the front pump of the Allison (prevents the delayed engagement issues), as well as the newer design NSBU (neutral safety back up lamp switch).

You'll enjoy the pulling power that no 5.7, 6.0, or 7.4 will match with approx the same MPG that the old Vortec 7.4's have. They have as close to the same pulling characteristics of a diesel that you can get.....without actually having to buy a diesel. 

As for actual MPG, after a few years of very close monitoring mine averages 8.3 - 9.1 MPG around town (loaded or empty). And 11.1 - 11.6 on the highway (loaded or empty). And anywhere from 55 - 85 MPH..cruise on or off makes no difference.


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## exmark1 (Nov 30, 2005)

I had a 2001 8.1 with 60 K on it I was going through a quart of oil every 500-700 miles and GM said it was NORMAL! WTF... I got 13 mpg at best averaged around 9 mpg but the power was amazing for a gas engine.


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## B&B (Nov 4, 2006)

exmark1;654229 said:


> I had a 2001 8.1 with 60 K on it I was going through a quart of oil every 500-700 miles.


Did you have the updated intake bolts installed? That cures a fair amount of the oil consumption.

But anyone who knows the big block Chevy's of any era knows they use some oil...the 8.1's are no different.


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## exmark1 (Nov 30, 2005)

B&B;654238 said:


> Did you have the updated intake bolts installed? That cures a fair amount of the oil consumption.
> 
> But anyone who knows the big block Chevy's of any era knows they use some oil...the 8.1's are no different.


I honestly don't know...I bought the truck used and only put about 10k on it before I got rid of it.


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## alivings (Jan 9, 2008)

I have an 02 GMC 2500HD with the 8.1 and I love plowing with this truck, Boss 8' superduty. I use Shell Rotela T synthetic and it burns about one quart every 3000 miles. I get an average of 13 mpg, it all depends on how you drive. This truck will pull anything you put behind it. I have a flowmaster cat-back and computer programmer, about $800 for both upgrades.


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## B&B (Nov 4, 2006)

alivings;655022 said:


> I have an 02 GMC 2500HD with the 8.1 and I love plowing with this truck, Boss 8' superduty. I use Shell Rotela T synthetic and it burns about one quart every 3000 miles. I get an average of 13 mpg, it all depends on how you drive. This truck will pull anything you put behind it. I have a flowmaster cat-back and computer programmer, about $800 for both upgrades.


A hand held programmer, or a custom tune? Big difference between the two.


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## alivings (Jan 9, 2008)

I have a hyperpac. I installed it in August so I am still messing around with it so far it's helped out with the gas mileage.


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