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Discussion Starter #1
I am a newbie. Hope I am posting in the right place.
I recently took a 2013 Equinox into the dealer for excessive oil consumption, which was covered by a class action settlement. The dealer made the repair, but I discovered something in the paperwork that is disturbing to me: The paperwork showed all of the parts, gaskets and hardware that you would expect to see when replacing all of the piston assemblies, but showed only one piston assembly replaced.
The class action settlement indicates that GM will replace the pistons (plural), and the dealer paperwork indicated that they replaced the pistons (again, plural). The paperwork listed only one piston assembly, and the service rep confirmed that they did only change one piston assembly. The part no. indicates that a piston assembly includes one piston, one wrist pin, and the rings. Their paperwork also indicated that the piston rings were stuck.
Does this make any sense to anyone else-- To tear down an engine that far and not replace the other three piston assemblies?
I haven't driven the car enough yet to see if the oil consumption problem is gone. I'm just wondering if anyone else has heard of this happening before. It does have 86000 miles on the odometer. Also, any suggestions?
 

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No, it doesn’t sound at all correct but given this is a dealer and this is a forced recall/mandated repair, anything is possible. The exact wording of the recall/suit may contain statements like replace up to a number of pistons/rings but might offer a limited replacement to the specific damage found after tear down. I wish I had more to offer but could you share with me more info on the class action suit as I too have a 2013 Equinox. What engine do you have?
Thanks.
 

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Discussion Starter #3
No, it doesn’t sound at all correct but given this is a dealer and this is a forced recall/mandated repair, anything is possible. The exact wording of the recall/suit may contain statements like replace up to a number of pistons/rings but might offer a limited replacement to the specific damage found after tear down. I wish I had more to offer but could you share with me more info on the class action suit as I too have a 2013 Equinox. What engine do you have?
Thanks.
No problem. I have the 2.4, 4 cylinder. The important thing to know is that the class action settlement provided for the warranty to be extended to 7 years, 6 months for the 2013 model (From the original in-service date) and limits miles to 120,000. Let me know if you need more info.
 

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All pistons and rings should have been replaced
You need to appeal to GM,

from Techlink....
Is says plural.. pistons... . Not singular piston...

Why?
new pistons (plural) because the compression ring groove will erode away.. resulting in oil consumption
When the gasoline charge is ignited by a glowing piece of carbon That sits on the upper compression ring , the resulting explosion of the charge erodes the steel on piston resulting in an oil consumption leak path...

Trom techlink... below...



2.4L Ecotec Engine Oil Consumption

August 6, 2013

Excessive oil consumption on some 2010-2013 LaCrosse, Equinox, Terrain and 2011-2013 Regal models equipped with the 2.4L engine (RPOs LAF, LEA) does not require engine replacement. If excessive oil consumption is confirmed after an oil consumption test, new pistons and piston rings should be installed.



Piston Ring Coating



The top compression ring in the new kit has a more robust coating on it that is designed not to wear as quickly as the original coating. Tests indicate that it wears about 4-5 times longer than the original coating.



If the top compression ring is worn, it will allow combustion pressure past it, which causes the oil control rings to be less effective and results in excessive oil consumption.



On 2010-2011 vehicles built before March 2011, there is a strong correlation between leaking high pressure fuel pumps diluting the oil and causing the ring wear. Due to this, check the fuel pump, balance chain, balance chain tensioner and timing chain for the proper part numbers. The updated fuel pump has an enhanced seal.



If these updated parts have not been installed during a previous repair, they should be replaced when the pistons and rings are replaced. Use field action #12313 if the balance chain and/or fuel pump is replaced.



Zebra Stripes



The pistons must be replaced because as the rings wear down, it starts to widen the piston ring groves. The worn grooves will not retain the new rings correctly.



The “zebra” stripping on the bore surface (Fig. 1) is not an indication of a cylinder bore abnormality, but rather a transfer of the ring material as it was worn down. The bores are still uniform and the new rings seal. The validation of the new ring pack was done on used blocks that had zebra striping. It’s not necessary to do any surface treatment to the zebra striped bores when installing the new pistons and rings.





techlink_aug_f01b
 

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Discussion Starter #5
Thank you for taking the time to reply and for finding the information. All of your comments back up the idea that they should have replaced all four pistons. I guess I'll start with the service rep and work my way up the chain of command. Just not sure where and how to start my conversation with corporate GM. Thanks, again!
 

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Discussion Starter #6
Update:
After additional research, I am 99.9 % sure that the part number listed for the piston actually represents a set of four pistons with wrist pins and rings (Even though the service rep told me it represented one piston).
So, after all is said and done, I think the dealer did the job properly, they provided me with a rental car, gave me a 6 month warranty on this work, the car seems to not be using oil and it cost me $0.00 I can't ask for more than that!
 
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