Looking At Possible 3500 W/ 8.1 Purchase

[MAC88]

looking to buy an 8.1 what are the things I should look out for? looking for an 8.1 in a 3500 ext cab 8 ft bed prefer srw but a dually would work to

[s-ten]

If you have never owned a big block before then don't be surprised if it uses about 1-2 quarts of oil every 3000 miles, it does not mean something is wrong they just use oil.

 

Other then that they 8.1 is a beast in about everything it does. I have used my dads to tow a medium sized tractor and I hardly even noticed it.

[outlawfab]

my boss had one for two months and got rid of it because of horrible fuel milage. ran well but only 225 miles on a tank solo and under 200 a tank towing a camper. only other issue is the way they put the crank sensor in.

[pm26]

Also, some 8.1's had cold start knock issues.

 

I almost bought a new Avalanche 2500 a few years ago, which came standard with this engine, but my neighbor knew someone who had one of those and he complained about terrible gas mileage: 9 MPG. So I changed my mind.

 

I would think tha this engine would be a s good as a diesel for heavy towing, however, for light duty and personal transportation, I would avoid a vehicle with this engine.

[MAC88]

cant complain about mpg's with 500 cubic inches

[s-ten]

cant complain about mpg's with 500 cubic inches

 

Exactly

[xwire]

cant complain about mpg's with 500 cubic inches

 

 

and the power to pull anything

 

I daily drive my 01 2500HD 8.1 w/ Allison, and love it, yea the gas mileage could be better but for the power under the hood I expected to lose some at the pumps, and still get way better gas mileage then my old 454 back in the day ;)

[10.90 hot rod]

If you have no budget constraints then buy the Duramax they are better on fuel from what I have heard. For what I paid for my 2500HD extended 4x4 with the 8.1/Allison, I calculated I would get the initial out lay of around $ 6 - 8000 more for the Duramax back in fuel savings in 7 years. You have to drive a big block powered truck to fully understand how awsome they really are. The plus side is : they will tow anything that a Duramax will, you can get gas anywhere anytime for the most part( depending where you live), they don't stink, repairs and maintainence is easy and cheap, and with stock exhaust they are whisper quiet. The negative side is the mileage ( which isn't much worse than a 6.0 liter) and they have cold start ticks( which many vehicles are plagued with these days). If you have a company that enables you to buy gas and write it off it's okay. I don't use mine for everyday driving year round. I drive an old winter beater and use the truck for pleasure and towing my race car trailer for the other three seasons.

[Hulk1999]

Don't buy it for Fuel Economy, buy it to embarrass fords and dodges. I have a lifted Big Block and i can still run them down and pass them. They think just because it a 3-3 1/2 ton truck it's slow. When they see my tail lights they are speechless! If you find a 496 get it cause GM's not offering it anymore for HD models. I also found out if you switch to a legit synthetic it doesn't eat as much oil. I'm down to half a quart every oil change.

 

Best thing to do is buy one, lift it, and run over imports that get in your way.

 

Hulk

[CG270ET]

I have the 8.1 in a 05 Yukon XL 2500 and no problems to date. It has plenty of power and is more responsive compared to the Sierra 2500 with a Duramax we test drove before deciding on the Yukon. We average 13.5 to 15 MPG depending on driving conditions and around 11 when towing the boat. As far as oil consumption I have used Mobile 1 from the first oil change and the most oil I have used between oil changes (every 3000 miles) is 1/2 quart .