This seems to be getting worse but i checked my dipstick today with a 35% oil remaining before change out and there was no oil on the stick... this has been an on going thing but i don't remember it being that bad before. so at first i was worried that the oil rings are leaking which maybe still is a possibility as the vehicle has 230000 miles on it but i saw that theres a valve cover replacement that moves the pvc opening and didn't know if that would even work for the express or if it's an entirely different issue all together. Whats the common issue and fix for this? it's an 08 4.8

 

Well if there aren't any visible leaks on any of the main seals, cooler lines etc. then you should compression test the block.

 

4.8 did not have oil consumption problems. the 5.3 did and they were related to the afm system which the 4.8 doesn't have.
how many miles did you drive between oil changes? Every engine uses oil to some degree. the oil consumption level that gm says is acceptable seems extreme.

if had 1 liter in 5000 kilometers; would not bother me for an old engine. high rpm driving will cause a higher level of oil consumption
following the oil life monitor is a mistake imo. the interval is to long.

to accurate gauge consumption you need to do oil consumption record. do an oil change and confirm the oil level is at the top of the full mark. record mileage and recheck level. the add mark to full mark should be 1 liter of oil.

end result if you are consuming oil internally...it needs a rebuild...or top it off and live with it.

 

I work at a lube center and i've run across this issue many times. Seems to be in most cases with vehicles that do a lot of idling. I know of engines that have been sent back to the manufacturer and had new sales put in and had the same results. I do not see this issue with your regular consumer vehicles with the eight quart 0W20 motors.