HateCarpetGuy

Well, after 380,000+ miles on my 2008 CC 5.3 (with a pile of receipts for keeping oil in engine), I'm done with Government Motors. Sent truck to auction and bought a Ford. However, he GM did fetch $7,500 at auction but only because it had been well-maintained, would crank and run smooth, decent tires, etc. New owner has no idea that AFM is OFF, valve cover/PCV replaced, seat belt dinger OFF, auto-door locks OFF, computer re-programmed in lieu of chip, AND that truck started to consume oil again.......I give up. But I do totally agree with Sr. Enthusiast that, geez Louise, how long has GM been building engines? and you struggle with keeping oil in crankcase??? Never again will I be a GM owner. You boys have fun, hatecarpetguy signing OFF for last time.

How to stop Oil Consumption: 1. Turn OFF AFM, this hair-brain system shuts down 4 cylinders for a virtually unnoticeable improvement in fuel mileage. This is to appease the EPA anti-oil folks that demand car companies achieve unrealistic standards. Turn off AFM and let your V8 run like a V8. Where do you think the saying "running on all cylinders" came from? I took mine to a speed shop that turned off AFM, when I asked the guy "so, what all did you do"? his response was "don't worry about the details - I just got the Govt out of your engine, it should run a long time now." 2. To be sure you don't have a piston - ring wear problem, do an old-fashioned compression check on all cylinders. This will let you sleep at night knowing that the bottom half of your engine is sound. Most problems are in the top half associated with AFM and the PCV valve built into the valve cover. (see above for part #) 3. Install the upgraded valve cover that has the new design that actually keeps oil where it should be and allows air back into the intake manifold, not oil. With the original design the oil blows out of the valve cover and accumulates in the valleys of the intake manifold. It then spills over into the engine as you ride, most noticeable at red lights on a hill. I performed the above steps on my truck at 180,000 miles and it has run super ever since. It runs better today than it did 4 years ago when I got it at 99K. Oil change at 5K, Tranny fluid at 50K, all fluids, belt, spark plugs at 100k. 2008 CC 4wd 5.3 Daily Driver - 360,000 miles

Guy Gene, FWIW: On my high mileage 2008 CC 4wd with 5.3, etc.: truck used to burn oil like they all seem to do. After reading up on the issue I went old school to confirm: I ran a compression check on all 8 cyl. (with AFM, I considered only checking 4, LOL). All cylinders were high and even, therefore rings were good. The topside was the culprit, I changed valve cover to get new PCV design and disabled AFM. No can was installed. ALL oil consumption stopped, like nearly zero. I do not have to add oil btwn changes, and its been like that for over 100K miles. I did not have to add "can", that seems to only treat the symptom, i.e. catch the oil vs stop the leak. I have been very pleased with the 2nd life in the truck. She likes running on all 8 cylinders all the time, gas mileage has not changed, oil stays in crankcase, computer tweak got the govt out of the engine. She actually runs better today than 4.5 yrs ago when I got it with 99K. Daily Driver - 353K

I did not do the shield in the oil pan, nobody can clearly explain what or how that will help oil consumption.. My truck runs great at 322K with AFM turned off and valve cover upgraded. No oil loss, no issues, driving it till she quits. It is really pissing off the local dealer that services the truck. They were fully expecting to sell another new one by now. I think high mileage vehicles well maintained is the only way to get your $ back from the high initial cost and the poor resale $,

STex, I think I may qualify to answer your question. My 2008 5.3 daily driver was using 2-3 qts/oil change with mileage out of wty. I researched oil consumption and frankly had a hard time believing that a modern GM V8 with all of its engineered glory could burn oil at that rate. I first went "old school" and had mechanic do a compression check. All cylinders looked great on bottom end rings/compression. So I went with the AFM / Valve Cover route. Apparently, the valve cover has the PCV valve built in, not the old plug-in the rubber-grommet type in the engines of old. This design allows oil to blow into top of intake manifold and then spill into cylinders when crevices fill up. I had dealer change the valve cover to upgraded cover (TSB), and took truck to a local speed shop and had AFM turned off, and motor tuned for everyday driving. After > 100K miles since work completed, I do NOT burn any oil. Repeat. Oil Consumption has STOPPED since upgrading valve cover and turning off AFM. Truck runs better today than it did 4 yrs ago while under warranty. Trust me, no oil loss at 5k oil change intervals. As of 2/1/14 my daily driver has 322,230 miles. No issues, other than I would not buy another GM.

I have not done anything in the oil pan, just the valve cover upgrade.

Time for me to re-visit: my 08 CC 4wd 5.3 w/ high mileage: I used to burn oil 2-3 qts/5K mi. Had a compression test done first to see if rings were bad, all good psi. Rolled the dice and had AFM turned OFF via computer reprogram at local speed shop, new PCV valve cover upgrade installed, new plugs installed just to start clean. After > 100K since improvements. there has been ZERO oil loss between changes, NONE. The old race car engine builder that reprogrammed computer said "these 5.3's are great engines once you get the 'bleeping' govt out of the motor". His words were aimed at the mechanically illogical AFM system, the theoretical striving for inc fuel ratings to pacify the EPA, and on and on and on. My mileage as of Dec. 20: 315K and still runs strong and I drive it everyday and would hesitate to road trip to wherever. Guys, you have to change to latest valve cover/PCV design to stop oil from free flowing onto top of intake to slurp over into engine, and my engine has seen no loss in fuel mileage (either hand calc or computer) by turning OFF AFM and running 8-cyl all the time. Like my dog prefers to walk on 4 legs instead of 2 or 3. Stand with Phil.

Here ya go JaBradt85, I drive about 1,000 mi/wk; 40-50K/yr. Like I said, truck runs fine now with no oil consumption after: AFM turned off, New design of PCV valve cover installed, use castrol 5w-30, even get it changed at local GM dealer at 5K (despite oil % showing 40-50% life left--I just have a hard time trusting a GM idiot light/message that nobody at the stealorship can explain how it calculates %). I just hope my pics come through below, by choice, I'm a newbie on the forum-post thing.

My 2008 5.3 used to consume 2-3 qts / 5,000 mi. until I changed valve cover and got the newer design of PCV valve. The original PCV design allowed for too much oil to pass out of valve cover and back into intake manifold. Oil would then pool in cavities of intake and spill over into cylinders when you stop at red light on incline, park on slope, etc. Since I changed valve covers (and you only need to do 1 side, I think there's a TSB about this) I have not burned any significant amount between oil changes. If you have not done this and you burn oil, I'd highly recommend looking into upgrading valve covers. I have almost 300K on my 2008 1500 CC 4x4 and it runs better now than it did at 100K when all these issues surfaced (oil consumption, plugs fouling, misfire error codes, AFM acting up, etc.) Turn as much OFF as you can, do not be buffaloed into thinking that your V-8 runs more efficient on 4 cylinders. AFM is a marketing ploy to sway EPA bureaucrats into giving Govt Motors a higher corporate fuel rating. Since turning off AFM, my truck runs smooth, gets same fuel mileage, and all 8 cylinders feel needed and not neglected!

08 1500 4x4 CC 5.3 about to roll over 300K by Labor Day. All majors original (tranny, transfer, engine). Runs better now at 293K than it did when I got it at 93K. Turned off AFM, replaced original valve cover with improved PCV design - stopped all excessive oil loss, had computer tuned at speed shop, oil change every 5K - castrol, change transmission fluid at 50K intervals, change all fluids at 100K interval, change plugs and wires when needed or 100K, driving lots of interstate and rough oilfield roads. Will continue to drive as long it will stay dependable and paid for. Old-school mechanic that did PCM tune said "these trucks will run fine once you get the Govt out of the engine".