8100 GM gas trucks

[Fshngyd]

Does anyone have the 8100 GM motor in their truck, how do you like it, gas mileage, maintenance? Please let me know what you think if you OWN one. Thanks in advance.

Kerry Keane
#217

[Phil T.]

Stop by your GM dealership or visit their website and get the tow ratings for that powertrain. The dealership should have a tow/haul booklet in their brochure racks. Remember, axle ratio affects things like load rating and mileage as much as the engine size.
As the owner of a big-block GM pickup, I'll remind you that you can have power or fuel economy, not both. If you have a big job to do, all that power comes from the fuel tank, and there's no free lunch.
Buy a big block only if you need it to tow your loads (or you like to drag race off stop lights or haul a trailer up mountains). Otherwise, buy a truck whose tow rating is about 1 1/2 times the loads you will tow/carry. The extra ability will result in much more durability.
Probably the last person to believe is a commissioned salesman who has a mortgage to pay, but doesn't ever actually haul anything himself. I'm lucky to live in cowboy/farm country. Our dealerships need to know the load ability of their trucks, and order accordingly.

[yellowlab]

If you post that question in the forum on pickuptruck.com you will probably get all sorts of information. I have found that board a great place to get answers to all sorts of truck questions.

[J.P.]

I work for a GMC dealer and we have sold a number of 8.1's. So far so good. Ihave only heard of one mileage report and that was 12mpg. This truck is driven to work and back -no freeway driving. I work in the service department and so far I've only worked on one 8.1. Hopefully this says something. Phil hit the nail on the head about towing needs.What are you towing? How far? How muchtime towing? Big blocks love gas, but do you really need a big block. If mileage is a big concern check out the Duramax diesel. So far the mileage rports on the diesel are 20-22mpg empty ane 15-17mpg towing. More torque with the diesel also. The 6.0 motor also is a good motor and mileage is about 17-20mpg from what I've heard. Take a good look at your needs with this truck and buy accordingly. Too many people buy big motors to go back and forth to work and do very little towing. Then they complain about mileage. Maintence is always the most important thing you can do to get the most miles out of your truck. Overkill on the maintenence is a good thing.

[Don__SD]

J.P. what have you heard about the Duramax I have had a tic tic tic in the motor and at 6500 miles they finally put in a new motor and the noise is still there. They and GM say they do not have a "fix" for the problem.

[J.P.]

I have not heard of any noises in the Duramax. Sometimes noises that are normal are transmitted into the cab by things like fuel lines rubbing on the body. normally you would not hear these in the cab. Check a couple other trucks to see if they make the same noise. So far this motor has been good.

[Firetiger(MN)]

I own a HD with a 6.0L, and it does not get 17-20 mpg. Whoever claims those numbers is pulling your leg or not calculating their mileage correctly. I'm sorry, but that just isn't a real life estimate. From all the people I've talked to with the 6.0, with varied vehicle configurations, not one has mentioned anything over 16 empty on a consistant basis....15 if you are lucky.

Just thought I'd throw that out there for anyone who is interested. The 8.1L is a power horse from what I've read and heard. Mileage isn't that far off from the 6.0, but drops a bit when towing. It also comes with the Allison automatic transmission to handle the torque.

[J.P.]

I can only tell you that 2 different people got this mileage from their trucks. I don't know how true it is but I do know that both guys are easy drivers. I would compare their driving habits to watching grass grow. Mileage varies so much who can you believe? Personally, you buy a truck to work. Mileage is secondary. Get a truck that suits your needs as far as towing and don't worry about mileage. I just talked to the guy with the 8.1 and he gets 11-12 city and 14mpg highway. Power is awesome and 0-100mph is unreal. He used to own a 454 before.

[Fshngyd]

Here's the thing, first I pull a 20' boat all spring, summer and Fall, but the distance I pull is only about 20 miles a day, no big deal there, other than that I pull nothing else except a enclosed trailer for Sports shows. The thing is I can get this truck at a great price, I have had a dealer friend of mine looking for about 6 months and this is what he came up with, except for the 8.1 it has everyting I wanted, crew cab, leather, CD and all the other goodies you need to pull a boat down the road with. At the present time with gas prices the way they are it does not bother me, but that can only last for just so long. Thanks for your posts on this subject.

Kerry Keane
#217

[J.P.]

Mileage does not seem to be a big factor. If you can save money now go for it . This motor won't disappoint you. Personally I think the new motors from GM are all good. I fix a lot of the old ones but hardly any new ones.

[Goldpig]

Who is claiming that kind of mileage with a 6.0L? I have and witnessed that kind of mileage on the Duramax HD combo's, but have never heard of anyone claiming those numbers on any other GM engine. Thank you.

[RVRRAT]

>Mileage does not seem to be a big factor. If you can save
>money now go for it . This motor won't disappoint you.
>Personally I think the new motors from GM are all good. I
>fix a lot of the old ones but hardly any new ones.
KEY WORD NEW

[PWSR91]

I have one in an Avalanche. I have 1250 miles and love it so far. 15mpg, 17mpg, 15mpg so far on fill ups. Drives great and is quite fast. Havent towed with it yet, but will tues when I go to Huron. If you need the power you'll love it, if you just want the power you'll reallllly love it
Phil Wilson Sr. #91

[J.P.]

Sorry if I mislead anyone with the word new. What I meant was the new design motors that have been out since 1999. 4.8 5.3 6.0 8.1 and the Duramax. Some of these trucks have 60,000-100,000 miles on them and never had a problem. My opinion is that GM is doing more research on these engines than they did in the past. As far as the mileage reports, I was not impling that all 6.0's are getting this mileage. Mileage is affected by so many things, driving habits, temp., what kind of gas, load, etc. My main point was that you buy a truck to suit your needs as far as towing , how much time is the truck used for towing vs just driving back and forth to work etc.

[SLS]

Check this web site www.thedieselpage.com for all the information on the new GM trucks, gas and diesel. Go to the web site and then click on FORUM for the different message boards on the GM truck your interested in. I have the Duramax and would stongly recommend for power and fuel economy. It is also very quiet for a desiel.