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  1. #31
    Former Member
    Join Date
    Apr 2012
    Location
    Reading, PA
    Posts
    291

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    Quote Originally Posted by Lerch98 View Post
    OK, so what is this decarbonization. Is this where they pour something into the intake or gas to clean the carbon off the valves.
    Here is Wisconsin we have what is known as a good German tune up. Take the vehicle out on the highway and romp on it and blow the carbon out. When you are doing this have a friend (preferably a Chevy buddy) follow and see if the truck is puffing out blue smoke or just black. If black smoke, repeat until clean but don't get busted by the highway patrol.

    You talk about the carbon deposits in the tail pipe. This depends on how you drive (not a rip). But if you drive on the highway to work (say for a half hour or more everyday) the exhaust will be clean. If you drive around town and don't really get the vehicle hot there still will be carbon in the pipes.

    Carbon forms on the rings and in the ring lands (grooves in the piston) and prevent the rings from floating freely in the lands...this keeps the rings from controlling oil and blow-by. I'm surprised someone hasn't used a leak down test to diagnose this?? To decarbonize, they add a solvent that soaks into, and dissolves the carbon, thereby allowing the rings to move freely again...driving it hard won't do this. There is a homebrew to do similar in small engines, not that I recommend doing this to a $$$$$$ truck under warranty; but I've used Kroil before to free up stuck rings in Gravely and small Kohler engines. I can't tell by their description if its a fuel issue or oil issue that causes the carbon??

    Carbon deposits in the tailpipe are normal under all driving conditions...its a byproduct of the combustion process (incomplete combustion), which happens even at WOT.

  2. #32

    Default

    the leak down test is very good point. If that engine is that carboned up that rings could get stuck, the German tune up would not be a good idea. But I guess it is hard to believe that a late model vehicle could be so carboned (or coked) up that that the rings would get stuck. As previously mentioned what do the plugs look like.

    As for tail pipe soot. I just went outside and checked my truck....Tail pipe is clean on the inside.

    As for Kroil to free up the rings.... I have seen where an engine is seized up (rings stuck) and ATF was squirted on the the cylinders by removing the plugs and putting in a few table spoons in and letting it soak for a couple of days. Repeat the process once or twice again and then turning the engine over. Is this what you are talking about using Kroil, right into the cylinders and let it soak? I have also heard of old timers putting Kroil in the gas tank.
    Lerch
    This is Chevy Country.

  3. #33

    Default

    I can't believe what passes for service at some dealerships. Stay on top of the issues, and don't be afraid to speak your mind. Pouring some magic elixer into an engine and pronouncing it cured went out with Capone! Any proper tech will tell you, adding solvents to a running engine, or soaking one with them can cause oil to breakdown. Even if newer oils are imune, they still get swept away, leaving many parts unprotected. This causes premature wear, and is a poor substitute to a proper strip down, cleaning, inspection, and reassembly. If I was gonna tell a customer their truck was ready to take them places, I would want to be SURE. Try telling me the oil level rises after cooling down, and I'll call you a liar, and report your name to corporate HQ. Good luck all.
    Brian L.




    Brian Larson CST. KC9DAK.
    Janesville WI.
    87 GMC G20 6.2 diesel.

  4. #34

    Default

    It's under warranty. Jeremy should play by their rules as it costs only them to do so. Failure to play by their rules might result in them claiming it's no longer covered ... so as long as he has a solid warranty still in play ... he really needs to play it their way. After the warranty is expired then it's off to independent mechanic land, for sure!

  5. #35

    Default

    So apparently they went in and supposedly what they'd planned to do had already been done. When was it done? That's a really good question. Maybe they snuck over in the middle of the night and abducted my truck out of sheer concern for the state of my oil consumption.

    Anyway, so they said since it was still so bad despite that work having already been done, they decided to go ahead and move to the next step of replacing the pistons and gasket seals. I'm not currently a fan of being in another country while my wife deals with this so I'm emailing them to try to get an update as well.

    I'm not sure what good new pistons will do if they're not sure they've fixed the original consumption issue. Oh well. The saga goes on. As long as I keep getting new parts and it gets fixed eventually I'll be nice. Maybe I can figure out a way to blame the dents on the hood on oil as well.

    To Be Completed (Eventually):
    6" BDS Suspension lift | KingShocks Front and Rear Coil Overs | 4.56 Gears | 35" A/Ts (TBD) | Cervinis 07-12 Silverado Ram Air Hood | Fab Fours Front Winch Bumper (CS07-H2051-1) | Fab Fours Full Size Rear Bumper (CS07-W1850-1) | RX-2 Series Main Grille (Black) | Line-x Bed and wheel wells | Skid Plates | Rizor Automated Tonneau Cover | Custom Bed Insert | RBP RX-3 Series Nerf Bars | Kenwood Excelon DNX9990HD | JL Audio Stealthbox (2x500RMS) | JL Audio HD 1200/1 Class D Mono Amp | JL Audio C5-653 Components (Front) | JL Audio C5-650 Components (Rear) | JL Audio Slash v2 300/4v2 Class A/B Amp

  6. #36
    Former Member
    Join Date
    Apr 2012
    Location
    Reading, PA
    Posts
    291

    Default

    Quote Originally Posted by Jeremy09LTZCrew View Post

    I'm not sure what good new pistons will do if they're not sure they've fixed the original consumption issue. Oh well. The saga goes on. As long as I keep getting new parts and it gets fixed eventually I'll be nice. Maybe I can figure out a way to blame the dents on the hood on oil as well.

    Keep in mind it was one that led to the other...

    The oil consumption from the original problem caused the coking of the piston rings. They fixed the original issue, but the coking still remains on the pistons which causes the oil consumption. Once they have the pistons and rings replaced, the problem should not come back since they have fixed the original problem.

  7. #37

    Default

    Right, that I get. Here's my issue. It was taken in a couple days ago for the oil consumption test. It was down 2 quarts after 1100 miles. Therefore, the issue was still at work. They opened it up and state the valve covers and oil deflector shield have already been replaced. If that's the case, and I'm not sure how it would be, then the issue wasn't addressed. Therefore, replacing the pistons will just subject the new pistons to the same abuse.

    To Be Completed (Eventually):
    6" BDS Suspension lift | KingShocks Front and Rear Coil Overs | 4.56 Gears | 35" A/Ts (TBD) | Cervinis 07-12 Silverado Ram Air Hood | Fab Fours Front Winch Bumper (CS07-H2051-1) | Fab Fours Full Size Rear Bumper (CS07-W1850-1) | RX-2 Series Main Grille (Black) | Line-x Bed and wheel wells | Skid Plates | Rizor Automated Tonneau Cover | Custom Bed Insert | RBP RX-3 Series Nerf Bars | Kenwood Excelon DNX9990HD | JL Audio Stealthbox (2x500RMS) | JL Audio HD 1200/1 Class D Mono Amp | JL Audio C5-653 Components (Front) | JL Audio C5-650 Components (Rear) | JL Audio Slash v2 300/4v2 Class A/B Amp

  8. #38
    Jr. Apprentice
    Join Date
    Apr 2008
    Location
    Harpers Ferry WV
    Posts
    14

    Exclamation Excessive oil consumption 5.3 Al engines with AFM -TSB issued

    Quote Originally Posted by Jeremy09LTZCrew View Post
    Right, that I get. Here's my issue. It was taken in a couple days ago for the oil consumption test. It was down 2 quarts after 1100 miles. Therefore, the issue was still at work. They opened it up and state the valve covers and oil deflector shield have already been replaced. If that's the case, and I'm not sure how it would be, then the issue wasn't addressed. Therefore, replacing the pistons will just subject the new pistons to the same abuse.
    I've traded my older Tahoe and Avalanche for newer '12 and '13 Avalanches even though the vehicles were running fine because I didn't want to run into oil burning issues in the future out of warranty. Since I have Avys I frequent the Chevy Avalanche Fan Club (CAFC) site and this issue is well documented by posts and TSBs - likely since the affected engines have been used in all post '07 Avys, and maybe not to that extent on all other GM truck lines. Seems that the 5.3 aluminum engines that have AFM (4/8 cyl. controls) have various problems with oil consumption as the age.....seems that when switching from 8 to 4 the oil spray is discharged into the sump near the #7 cylinder and with time clogs the oil control rings, oil gets past, and is burned in #7 cylinder....fouls the plugs and you get oil burning and eventually a misfire. The '07 & '08 corrections change the valve covers and later '08/'09 models add an oil baffle installed in the sump to shield the spray from #7 cylinder. Corrective actions include solvent cleanings to clean/unjam the #7 rings installing new valve covers &/or baffle, however if the chemical treatment cannot unstick the (oil control) rings, the problem will remain. Visit and check the posts on AFM for further info.

    Many people on the CAFC site say they are using programming tuners to reprogram the vehicle to operate on 8 cylinder only to prevent the problem.....some have claimed that this works although it probably voids any warranty .....further the dealers may not do this because it defeats one of the vehicles major emissions features. I'm attaching one of the many TSBs issued on this problem:

    Bulletin No.: 10-06-01-008B
    Date: March 07, 2011

    Subject: Engine Oil Consumption on Aluminum Block Engines with Active Fuel Management (AFM) (Install AFM Oil Deflector and Clean Carbon from Cylinder)

    Models: 2007-2009 Cadillac Escalade, Escalade ESV, Escalade EXT 2007-2009 Chevrolet Avalanche, Silverado 1500, Suburban, Tahoe 2007-2009 GMC Sierra 1500, Sierra Denali, Yukon, Yukon XL, Yukon Denali, Yukon Denali XL 2008-2009 Pontiac G8 GT Equipped with Aluminum Block V8 Engine with Active Fuel Management (AFM) (RPOs LC9, LH6, L76, LFA, L92) with Greater than 45,000 km (28,000 mi)

    Supercede: This bulletin is being revised to add the 2009 model year and new Correction information for the 2009 model year - left rocker arm cover replacement. Information has also been added after step 9. Please discard Corporate Bulletin Number 10-06-01-008A (Section 06 - Engine/Propulsion System).

    Condition

    Some customers may comment about engine oil consumption of vehicles with higher mileage (approximately 48,000 to 64,000 km (30,000 to 40,000 mi). Verify that the induction system is assembled correctly and that there is no evidence that the engine has been ingesting dirty air due to a mis-assembled induction system. Also verify that the PCV system is functioning properly. If diagnostic procedures indicate that oil consumption is piston/piston ring related, verify that oil consumption is less than 3,000 km (2,000 mi) per liter/quart. If these conditions are met and oil consumption is less than 3,000 km (2,000 mi) per liter/quart, perform the service indicated in this bulletin.

    Cause

    This condition may be caused by oil spray that is discharged from the AFM pressure relief valve within the crankcase. Under most driving conditions and drive cycles, the discharged oil does not cause a problem. Under certain drive cycles (extended high engine speed operation), in combination with parts at the high end of their tolerance specification, the oil spray quantity may be more than usual, resulting in excessive deposit formation in the piston ring grooves, causing increased oil consumption.

    Correction

    2009 Vehicles Only

    Important This left rocker arm cover is NOT to be used on 2007-2008 vehicles because of the calibration of the PCV orifice being different in 2007-2008.

    A new left rocker arm cover has been released for 2009 engines. Technicians should replace the left rocker arm cover with GM P/N 12642655. This rocker arm cover has relocated PCV drain holes that prevents PCV pullover into the intake manifold. Refer to SI for Valve Rocker Arm Cover Replacement - Left Side.

    2008-2007 Vehicles Only

    To correct this condition, perform the piston cleaning procedure as described in this document, and install a shield over the AFM pressure relief valve per the procedure outlined in this document. Monitor oil consumption after this repair to ensure oil consumption has improved to acceptable levels. If this repair does not correct the condition, it may be necessary to replace the piston assemblies (piston and rings) with new parts.

    Important It is critical in this cleaning process that the engine/fuel injector cleaner remain in the cylinders for a minimum of 2.5 hours to fully clean the components. The cleaner solution must be removed before a maximum of three hours.

    1. Verify the oil consumption concern following Corporate Bulletin Number 01-06-01-011F. If oil consumption is found, continue on with this bulletin.

    2. Remove the spark plugs and ensure that none of the pistons are at top dead center (TDC).

    3. Clean the pistons by putting 118-147 ml (4-5 oz) of Upper Engine and Fuel Injector Cleaner, GM P/N 88861802 (in Canada, use 88861804), in each cylinder. Allow the material to soak for at least 2.5-3.0 hours, but no more than three hours and then remove the cleaner. A suggested method of removing the cleaner is cranking engine over. Make sure to unplug the ignition coils and fuel injector before cranking the engine over. Also make sure that the painted surfaces are covered so no damage is done.

    4. Remove the oil pan. Refer to Oil Pan Replacement in SI.

    5. Remove the AFM valve.

    6. Install the new shield, GM P/N 12639759, and tighten the AFM valve to the oil pan to 28 Nm (20 lb ft).

    Important Ensure that the engine cleaner is thoroughly removed before reinstalling the spark plugs. Failure to do so may result in a hydro-lock condition.

    7. Reinstall the spark plugs. Replace the spark plugs if necessary due to full of carbon.

    8. Reinstall the oil pan. Refer to the Oil Pan Installation procedure in SI. Replace the oil pan gasket if necessary. Refer to the parts catalog. Replace the engine oil if necessary.

    9. Re-evaluate the oil consumption. Document on the repair order. If the oil consumption is still greater than 0.946 L (1 qt) in 3,200 km (2000 mi), replacement of the pistons and rings will be required.

    Important Some minor scratches may be noticed on the cylinder walls during piston and ring replacement. If the scratch cannot be felt when running your finger nail over it, the scratch is considered normal wear and the block or engine should not be replaced.

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