Stumbled onto this TB while researching and di the mod, worked! Didn't see it on the site and thought it would be a good one for the tip/tricks sticky:
High Oil Consumption On 2001-2002 GM 8.1L
VIN G Engines
The AERA Technical Committee offers the following information regarding higher than
expected oil consumption for 2001-2002 Gm 8.1L VIN G engines. That amount would be a
quart or more of oil to 100 gallons of fuel used. Engines use various amounts of oil depending
upon the severity of their duty and load conditions.
It has been determined that in this engine there may be oil vapor entering the intake
manifold due to insufficient intake gasket applied load. To resolve this condition new service
intake manifold bolts have been developed. Those bolts are available with Part
#12561518 and ten are required. Additional torque has also been added to the installation
procedure below.
Step 1. In the order of sequence shown below, loosen and replace one bolt at at
time. Insert a new bolt and torque it immediately to 44 inch pounds.
Step 2. After all ten bolts have been replaced with new bolts tighten each bolt in
sequence to 71 inch pounds.
Step 3. Tighten all bolts in sequence to a final torque of 106 inch pounds.
This procedure should also be used anytime the intake manifold gaskets are being
installed and older service manuals should be replaced with this current information.

http://www.jasperengines.com/pdf/8.1_Oil_Consumption.pdf here is the link so you can see the diagram.

I took my rig to someone to do it and they jumped righ on it, so no first hand knowledge on install on my part.

Hope this helps!

Do you get these bolts from the dealership?

So you dont need to replace the intake gasket?

Thanks for the info just checked my vin and i have the G and my truck uses alot of oil when towing.Like 2 - 3 liters for less then 4000km driving.

Thanks for posting the info spomed1998.

83trekker,

Did a search on gmpartsdirect and this is what comes up

GM PART # 12561518
PACK QTY: 1
GM LIST: $4.46
OUR PRICE: $2.54
DESCRIPTION: BOLT

Thanks for posting the info spomed1998.

83trekker,

Did a search on gmpartsdirect and this is what comes up

GM PART # 12561518
PACK QTY: 1
GM LIST: $4.46
OUR PRICE: $2.54
DESCRIPTION: BOLT

awsome i wonder if they ship to canada, if you do this please let me know how it turns out, i am scared of wrecking the intake gasket. But i would love to fix the oil consumption i work my 8.1l hard but thats just too much oil use.

Well guys, from the locals here with the 8.1L's and EVEN the dealer, I was told this didnt help at all. I searched the internet about a year ago and found numerous people that said the same thing...its not worth the hassle and DID NOT fix the oil consumption problem. Just saying...but if someone does it and it DOES work, more power to you!