I located this interesting thread [via PUTC] on oil consuption in the current breed of 8.1L Intake Manifold bolt TSB - may be worth following and looking into. 
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8.1L Oil Consuption Alert And TSB
- Thread starter gandolphxx
- Start date
Have you checked your manifold bolts
Let me know what you find. I'll check mine in the next couple of days. Good info for us with the 8.1. ?Thanks..
Gary
Let me know what you find. I'll check mine in the next couple of days. Good info for us with the 8.1. ?Thanks..Gary
You may want to track this source also PUTC thread on this issue
W
wbull
GUEST
I have a 2500 with the 8.1 engine. I had to get my first oil change early at 2500 miles because the level was so low. When I complained about the loss of oil on a new engine the dealer gave me a story about the oil loss being common on the 8.1 and it should stop once the valves properly seat themselves. The service person continued to tell me that GM has said this is nomal and not cause for concern that is should correct itself by 10,000.
I'll keep an eye on the dip stick and a copy of the Intake Manifold bolt fix for my next dealer visit.
I'll keep an eye on the dip stick and a copy of the Intake Manifold bolt fix for my next dealer visit.
I went through three quarts during breakin. The dealer told me it's normal. After the first oil change per the indicator, my consumption has been none to very little. This time, the dealer appears to have been correct. 
This TSB info is interesting none-the-less. Time to go check the bolts tonight.
This TSB info is interesting none-the-less. Time to go check the bolts tonight.Have 2500 miles on 2002 2500 AV--no oil burn at all--but did retourqe the intake bolts to 7 ft/lbs on the hunch as discussed on this forum at 900 miles.They were not what I would call loose--but did snug down nicely starting from the mid area and working out.,Thanx for the info!
Gandolphxx, There is no doubt... "you da man!"
J
jeter
GUEST
I have had the same problems with oil consumption in my 2500 8.1 liter. The first three oil changes were low by at least a quart at or before the 3,000 mile mark. After reading about the consumption problem I told the dealer the pcv valve might be the problem. He suggested the intake manilolld bolts be changed because of the tech bulletin. After the bolt change I notice the oil down one hole after waiting 20 min to check the dip stick. Dealer says I am reading the stick incorrectly. Each hole on the stick represents 1/8 th of a quart so one hole down in 1,000 miles is normal. How do you read the dip stick? 