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GM response to failing LS7 engines

164K views 97 replies 40 participants last post by  TacoSauced 
#1 · (Edited by Moderator)
Hello all,

LS7 Valve guide issue summary:
• Affects a small, number of '08, 09 ’10 and ’11 Z06’s
• GM discovered the condition through our cylinder head warranty data involving a very small percentage of our vehicles.
• Through inspection of returned heads, it was determined that a machining error in the valve guide had occurred at our head supplier.
• The quality issue has been contained as of Feb 2011 with 100% inspection of all heads.
• The most common customer complaint has been excessive valve train noise.

However if the condition is not addressed, it could result in engine failure. To date, where this condition has been observed, it has occurred early in the vehicle life.

What customers need to know: They should drive and enjoy their vehicles without fear. If their car demonstrates this condition, they are likely to hear unusual valvetrain noise first. If you have a concern regarding this issue on your personal vehicle feel free to contact me through private message on this forum and we will work to assist in resolving your concern. Feel free to contact me through Socialmedia@gm.com please put attention Evan in the subject. As always, vehicles that have modifications to the powertrain or the calibrations, are no longer covered by GM's warranty.

Sincerely,
Evan, Chevrolet Customer Service
 
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#2 ·
It is interesting that software mods void a warranty of a clear failure in manufacture.

As always, vehicles that have modifications to the powertrain or the calibrations, are no longer covered by GM's warranty.
How can GM declare a warrant void for admitted manufacturing defect when aletered software in no way shape or form is the cause of the manufacturing defect.

Sounds like grounds for a class action suite against GM. If I was an attorney I would take it on pro bono.

Has the been Magnuson–Moss Warranty Act been repealed?
 
#3 · (Edited)
Different from failures due to design issues as it is federal law as to EPA as the car was certified for public sale with the PCM GM calibration car was tested to and law that no one other then GM can make calibration changes since it would effect smog output and could cause smog devices to degrade
Magnuson–Moss Warranty Act cannot super exceed EPA law

Also if GM spec'd the powertrain for a maximum of 470 ft/lb torque and 505 HP any tune changes forcing those to be higher then it is beyond the warrantied design specs.
 
#4 · (Edited)
Different from failures due to design issues as it is federal law as to EPA as the car was certified for public sale with the PCM GM calibration car was tested to and law that no one other then GM can make calibration changes since it would effect smog output and could cause smog devices to degrade
Magnuson–Moss Warranty Act cannot super exceed EPA law.

But read the OP - it specifically states that due to design and manufacturing defect the engine can fail.

Modding the PCM may void the part of the warranty covering the PCM and mechanical failures due to over stress brought on by tuning, but it can not void the coverage of a failure due to the valve guide problem based on you modding the PCM.

Magnuson–Moss Warranty Act specifcally addresses this type scenario.

GM has an admitted failure and error in design/manufacture, so they try void warranty claim based on an unrelated component being modded.

Then again, severly stressed modded motors seldom run stock heads anyway.

Also if GM spec'd the powertrain for a maximum of 470 ft/lb torque and 505 HP any tune changes forcing those to be higher then it is beyond the warrantied design specs.
Except where the failure is due to the admitted valve guide manufacturing flaw.
 
#5 · (Edited by Moderator)
GM learned the hard way about the mods people did on the C5 or Fbody and then sneaky to get the dealer to repair failures from those mods under warranty since the dealer can care less as they are getting paid by GM

Now GM has written into new warranty solely about those types of mods and directly at any PCM or TCM calibrations. They are locked by EPA laws and means to modify them the locks were picked.

MMWA cannot overcome EPA federal law and the PCM is a smog device which cannot be modified even by GM without going back and getting federal testing done.

GM and feds consider it tampering with PCM software so it is not like buying a 3 party part to replace a OEM part

Look how much detail GM did just about PCM tunes

#09-06-04-026B: Identifying Non-GM (Aftermarket) Engine and Transmission Calibrations for V8 Gas Engines Using Tech 2 or Global Diagnostic System (GDS) - (Apr 7, 2010)

Subject: Identifying Non-GM (Aftermarket) Engine and Transmission Calibrations for V8 Gas Engines Using Tech 2® or Global Diagnostic System (GDS) Models: 2006-2010 GM Passenger Cars and Light Duty Trucks (Excluding Saab 9-7X) 2006-2009 HUMMER H2 2006-2010 HUMMER H3 Equipped with V8 Gas Powered Engines Only

General Motors is identifying an increasing number of engine, transmission and catalytic converter part failures that are the result of non-GM (aftermarket) engine and transmission control calibrations being used.

When alteration to the GM-released engine or transmission control calibrations occurs, it subjects powertrain and driveline components (engine, transmission, transfer case, driveshaft and rear axle) to stresses that were not tested by General Motors.

It is because of these unknown stresses, and the potential to alter reliability, durability and emissions performance, that GM has adopted a policy that prevents any UNAUTHORIZED dealer warranty claim submissions to any remaining warranty coverage, to the powertrain and driveline components whenever the presence of a non-GM (aftermarket) calibration is confirmed—even if the non-GM control module calibration is subsequently removed.

Warranty coverage is based on the equipment and calibrations that were released on the vehicle at time of sale, or subsequently updated by GM.

That’s because GM testing and validation matches the calibration to a host of criteria that is essential to assure reliability, durability and emissions performance over the life of the warranty coverage and beyond.

Stresses resulting from calibrations different from those tested and released by GM can damage or weaken components, leading to poor performance and or shortened life. Additionally, non-GM (aftermarket) issued engine control modifications often do not meet the same emissions performance standards as GM issued calibrations.


Depending on state statutes, individuals who install engine control module calibrations that put the vehicle outside the parameters of emissions certification standards may be subject to fines and/or penalties.

This bulletin outlines a procedure to identify the presence of non-GM (aftermarket) calibrations. GM recommends performing this check whenever a hard part failure is seen on internal engine or transmission components, or before an engine assembly or transmission assembly is being replaced under warranty.

It is also recommended that the engine calibration verification procedure be performed whenever diagnostics indicate that catalytic converter replacement is indicated. The PQC has a process to confirm the ECM/PCM calibration is GM issued. The PQC will require a picture of the engine calibration verification screen, as outlined in this bulletin, before authorizing any V8 gas powered engine replacement.

If a non-GM calibration is found and verification has taken place through GM, the remaining powertrain and driveline warranty will be blocked and notated in GMVIS and the dealership will be notified. This block prevents any UNAUTHORIZED warranty claim submission.

•Connect the Tech 2® to the vehicle.
•Go to: Diagnostics and build the vehicle.
•Select: Powertrain.
•Select: Engine.
•*Select: Engine Control Module or PCM.
•*Select: Module ID Information or I/M Information System if the Module ID Information selection is not available.
•*If "I/M information System" was selected, it may be necessary to select "Vehicle Information" in order to display the calibration information.⇒

If the CVN information is displayed as "N/A", it will be necessary to contact the TCSC (1-800-828-6860 English or 1-800-503-3222 French) to obtain the CVN information.
•Take a CLEAR digital picture of the Tech 2® Vehicle Information screen showing the engine Calibration IDs and Verification Numbers as shown above.
Retain the printout information and the Tech 2® screen photograph with the repair order.

•E-mail a copy of the picture to tacsnapshot@gm.com.

In the subject line of the e-mail include the phrase "V8 Cal" as well as the complete VIN and Dealer BAC. In the body of the e-mail, include the VIN, mileage, R.O. number and BAC.
Include a brief description of the customer concern and cause of the concern.

Note: The dealer will receive an e-mail reply after the calibrations have been validated. The e-mail reply will advise the dealer if the calibrations are OEM.

•Allow two hours for the PQC to verify the calibrations and set up the case details.⇒ If the PQC determines that the calibrations ARE aftermarket calibrations, DO NOT contact GM Technical Assistance to discuss warranty concerns on the aftermarket calibrations. ALL questions and concerns about warranty should be directed to the dealers Fixed Operations Manager (FOM), (Warranty Manager (WM) in Canada).

•You may call the PQC two hours after submitting the e-mail for authorization to replace the assembly. This will provide them time to receive, review and set up a case on the request.

Please be prepared to provide all the usual documentation that is normally required when requesting an assembly authorization from the PQC.Tech 2® Displaying All Zeroes for the Verification Numbers on the Calibration ID and Verification Number Screen If the Tech 2® that you are using displays all zeroes for the Verification Numbers as shown, then perform the following steps:
•Update the Tech 2® with the latest software from TIS2WEB.
•Turn OFF the ignition for 90 seconds.

•Connect the Tech 2® to the vehicle.
•Turn ON the ignition, and build the vehicle.
Observe the Tech 2® Calibration ID and Verification Number screen for proper operation.⇒
If the Tech 2® screen still does not display properly, then turn OFF the ignition for 90 seconds again.

Turn ON the ignition and observe the same screen for proper operation. Retrieving Calibrations From a Global A Vehicle
This information applies to the 2010 Camaro and is typical of the procedure that will be used on Global A vehicles.
•Turn OFF the ignition.

•Connect the MDI to the Data Link Connector (DLC) of the vehicle. Note: Use the USB port to make the following MDI connection:
•Connect the MDI to a PC or laptop that has been downloaded with the GDS application from TIS2WEB.

Note: At least one Diagnostic Package must be installed on the PC to perform diagnostics. If GDS was just installed, select: Add New Diagnostic Package and then select: a Diagnostic Package to download.
•Click: On the GDS icon on the PC.
•The Login Page will appear.
•Select: A User.
•The ID Screen will appear.
•Select: The serial number of the MDI being used.
•Select: Connect.
•Verify that the system status is ready by observing for a flashing PC light icon on the MDI.
•Select: Make, Model and Model Year, in order to build the vehicle.
•Click: Upload VIN, to allow the VIN to be reported to the PC. •At: The Verification step, turn ON the ignition, with the engine OFF.
•Select: Next Action.
•The Home Page will appear.
•Select: Next.
•The Diagnostic Screen will appear.
Note: Due to vehicle build, software and RPO variations, GDS may ask for additional information in Step 18.

•Select: Engine ID, if prompted.
•Select: Module Diagnostics.
•Select: ECM.
•Select: ID Information.
•The Diagnostics page will appear. Typical View of GDS Calibration History Screen Note: GDS is capable of displaying up to 10 Calibration History events.
•Select: Calibration History from the drop down menu in order to display the following items on the screen:
• Calibration History Buffer
• Number of Calibration History Events Stored
• Calibration Part Number History
• Calibration Verification Number History
•Select: Screenshot.
•Name and save the file in an appropriate folder.

•Select : Print, and retain a copy of the screenshot with the repair order.
•E-mail a copy of the screenshot to tacsnapshot@gm.com. In the subject line of the e-mail include the phrase "V8 Cal" as well as the complete VIN and Dealer BAC.

In the body of the e-mail, include the VIN, mileage, R.O. number and BAC. Include a brief description of the customer concern and cause of the concern.

Note: The dealer will receive an e-mail reply after the calibrations have been validated. The e-mail reply will advise the dealer if the calibrations are OEM.

•Allow two hours for the PQC to verify the calibrations and set up the case details.⇒ If the PQC determines that the calibrations ARE aftermarket calibrations, DO NOT contact GM Technical Assistance to discuss warranty concerns on the aftermarket calibrations. ALL questions and concerns about warranty should be directed to the dealers Fixed Operations Manager (FOM), (Warranty Manager (WM) in Canada).

•You may call the PQC two hours after submitting the e-mail for authorization to replace the assembly. This will provide them time to receive, review and set up a case on the request. Please be prepared to provide all the usual documentation that is normally required when requesting an assembly authorization from the PQC. Warranty Information

• The Dealership Service Management must be involved in any situation that would justify the use of labor operation Z1111. • Notify the Fixed Operations Manager (FOM) (Warranty Manager (WM) in Canada) of the situation.
• All claims will have to be routed to the FOM (WM in Canada) for approval.
• Please refer to Corporate Bulletin Number 09-00-89-016, Labor Operation Z1111 - Suspected Tampering or Vehicle Modifications for important information.

For vehicles repaired under warranty, use: Labor Operation Description Labor Time Z1111 Suspected Tampering or Vehicle Modifications 0.2 hr GM bulletins are intended for use by professional technicians, NOT a "do-it-yourselfer".
 
#7 ·
There is no super car that has a 5 yr 100K warranty. I have an extended I think for 2 more years. That's why I keep it stock. I would like to do some things but I won't. They have to keep their warranty work to a minimum for mod guys. They are taking from our pool too just like insurance fraud. I actually don't blame them(GM) as most all of these LS7 explosions are modded. Few are stock and I believe it is a valve guide issue. But that being said they could sell this car w/ a 3 yr 36K and guys would buy it. I'd rather they crack down on guys who CHOSE to throw their warranty out the window. I had a BMW that I liked a 06 750. 4 year warranty and an extended that didn't cover alot was over 4000 dollars. for only two more years. Our warranty and the price of an extended is very reasonable. Players should pay their own bill.
 
#9 ·
T I actually don't blame them(GM) as most all of these LS7 explosions are modded. Few are stock and I believe it is a valve guide issue. Our warranty and the price of an extended is very reasonable. Players should pay their own bill.
I know a guy who had an 06Z06 (not me), and he wanted to put a cam in it after the warranty had run out. When the heads were taken off (it was stock), The valves were so loose in the guides and the ports had taken such a beating that the shop couldn't save the heads. He had to get new heads and he sold it after that.

And Jim, I agree with your last statement. If you wanna play, you gotta pay! :yeadog:
 
#12 ·
Sound travels, even more on aluminum engines

Check or have dealer look at this TSB

08-06-01-019: Rattle/Tapping Type Noise Heard Under Hood (Diagnose and Replace Engine Oil Tank Transfer Tube Seal (O-Ring)) - (Aug 13, 2008)


Subject: Rattle/Tapping Type Noise Heard Under Hood (Diagnose and Replace Engine Oil Tank Transfer Tube Seal (O-Ring))


Models: 2006-2009 Chevrolet Corvette Z06

2009 Chevrolet Corvette ZR1 with 6.2L or 7.0L Engine (VINs R, E -- RPOs LS9, LS7)

Condition

Some customers may comment on a rattle or tapping type noise that is heard under the hood at just above idle, usually 1200 to 2200 RPM.

In some cases, this noise may also be heard on the inside of the vehicle and be more pronounced on the passenger side.

Cause

This noise may be caused by the internal transfer tube in the engine oil tank hitting the inside of the tank cover.
The seal (o-ring) that secures the tube in place may split and slide down the tube allowing the tube to be loose.

Correction

Diagnose the noise by raising the vehicle on a hoist and holding the throttle at about 1500 RPM to duplicate the condition.

Use a stethoscope or chassis ears and place them on the side of the engine oil tank. If the noise is detected, perform the procedure outlined below.
If the noise is not detected, continue following published diagnostics in SI.

Remove the engine oil tank from the vehicle. Refer to the Oil Tank Replacement procedure in SI.

Remove the eight bolts that secure the tank top.

Separate the tank. Check the seal (o-ring) for proper position and damage. Replace the seal (o-ring) if damaged with P/N 24576940.

Reinstall the tank top and secure with the eight bolts.
Install the engine oil tank into the vehicle.
Refer to the Oil Tank Replacement procedure in SI.

Parts Information
Part Number ---------------- Description ---------------- Qty

24576940 Seal (O-Ring), Engine Oil (Tank Transfer Tube) 1
 
#13 ·
^^ Thanks. I actually had my 08 Z oil tank replaced for this noise at 1700 miles... It hasn't returned. The noise of which I speak is the engine noise from new in all these engines. Not too loud, and "normal". I'm confident my egine is running well now, but what does one needing a GM TSB repair sound like?
 
#17 ·
Probably not covered after the warranty expires.

Since the batch of bad heads has been used for multiple years, it probably would be impossible to identify what engines they went on.

The problem is that not all of the heads were bad, probably sloppy qa or none at all at the cylinder head supplier let some of the bad ones into the supply chain.
 
#18 ·
Hello all,

LS7 Valve guide issue summary:
• Affects a small, number of '08, 09 ’10 and ’11 Z06’s
• GM discovered the condition through our cylinder head warranty data involving a very small percentage of our vehicles.
• Through inspection of returned heads, it was determined that a machining error in the valve guide had occurred at our head supplier.
The quality issue has been contained as of Feb 2011 with 100% inspection of all heads.• The most common customer complaint has been excessive valve train noise.
However if the condition is not addressed, it could result in engine failure. To date, where this condition has been observed, it has occurred early in the vehicle life.
What customers need to know: They should drive and enjoy their vehicles without fear. If their car demonstrates this condition, they are likely to hear unusual valvetrain noise first. If you have a concern regarding this issue on your personal vehicle feel free to contact me through private message on this forum and we will work to assist in resolving your concern. Feel free to contact me through Socialmedia@gm.com please put attention Evan in the subject. As always, vehicles that have modifications to the powertrain or the calibrations, are no longer covered by GM's warranty.

Sincerely,
Evan, Chevrolet Customer Service
That statement in bold is a bit laughable as there are already documented valve failures and excessive guide wear reports on new motors/heads with production dates after that Feb 2011 cutoff.
 
#19 · (Edited by Moderator)
Do not let this discourage anyone from buying a Z06. I had the same problem, and couldn't be happier with the response I received from GM. GM stands behind its product, and it is still a great company with tremendous bang for the buck products. I still have the Z, and couldn't imagine trading it for anything else!!!:usa: This article, on its face, is proof that GM is still going the extra mile to keep its customers happy.
 
#25 ·
I congratulate you on such a favorable outcome.

My experience was just the opposite. My showroom-stock 2006 Z06, with a bit over 38,000 miles, was found to have defective valve guides. Since my original 3/36 warranty (2006 warranties were only 3/36) had expired 2009, Chevy took the position that any repair costs were mine to bear. $4,000 later, out of my pocket, I have re-worked heads with stainless steel exhaust valves and bronze guides which I hope will last considerably longer than the OEM junk Chevy installed at the factory. It was my good fortune that the defective guides were detected before I dropped a valve, lest my repair bill would have been considerably more - some say as much as $17,000 for a new engine.

At any rate, based on my experience, I must take strong exception to anyone who says that GM stands behind their product. As far as I am concerned, with few exceptions, GM has essentially abandoned the C6 Z06 owner community.

They ought to be ashamed. I tell my story at every opportunity, and you can bet I'll never again buy GM. But then again, GM doesn't care either way.
 
#21 ·
I felt rather stupid, had a ticking sound as well. My car is undercover for the winter, and I've been dealing with a sporadic battery (hooked up to life support too), as well as the ticking.

I contacted the dealership last week concerning the battery, a tech came to my house Friday (small town, friendly dealer) with a new battery (car is still under warranty). He installed the battery, car fired immediately, and then asked him about ticking....he found a spark plug that was arcing as the cover was not pressed all the way down.

Both problems solved, hurrah!
 
#24 ·
I have a '07 Z06 that had an engine failure ( rod through the engine block) while I was traveling to work. Denied warranty work due to my trying a tuner to see if it would help gas mileage/performance. I saw no difference...took off the program and a month after took off, the engine failed. Blamed it on tuner. BS! I still have old engine and need assistance to recoup the 17k + I had to shell out to replace short block only. Told by many that this could not cause catastrophic failure but GM held fast on their position. I'm not giving up but I need a lot of help. Anyone?
 
#33 ·
Members, I have a growing concern, having been through the engine failure process myself, that those of you who have not had the joy of experiencing the problem seem to think that LS7 failure is nothing more than an urban legend. Luckily, GM and I were able to join hands and sing kumbaya in the end, but it seems that this forum is gaining a troubling skepticism towards the fact that there are some known problems with our engines, particularly regarding the valve springs, rocker arms, and rocker arm bearings.

I agree with all of you that GM is not, and should not, be under any responsibility to fix failures that are outside of warranty, but come on, let's try to be a little more supportive of those that are going through engine problems. I guarantee you that as the miles stack up on the LS7's, we are going to hear more and more stories of failures. My advice is that everyone should do a little bit of preventative maintenance and replace their valve springs at 25k.

That being said, I welcome all brothers and sisters that are having engine problems. There are some folks on this forum with a considerable wealth pf knowledge that will be of great assistance to others in a time of need. The LS7, is in my opinion, the greatest V8 of this generation, yes the 4.5 liter from the Ferrari 458 included, but just like all engines, it has some points that could be improved. Now let's rally around our brothers and sisters and support them.:usa:
 
#34 ·
My concern is a bit different....

My concern is that perhaps someone is not reading entire posts and thinks that this so-called "non support" has to do with not acknowledging some LS7 engine issues, including valve issues.

If someone points out that car manufacturers, including GM, are unlikely to provide free parts and service for cars out of warranty, I don't see that as non acknowledgement of certain defects that have shown up in several cars nor do I see that as viewing said problems as "urban legends".

My concern is that someone who posts that GM doesn't give a damn about anyone and will never buy a GM product again may be considered by some as a 'brother or sister' in need of support.

...but that's just me.

Mike
 
#35 ·
To conclude or even assume claimed design failures some first has to look at said failures and remove all those where

1. LS7 was abused
2. improper shifting
3. crap mods
4. hacked tunes
5. Wrong type of oil used ( see it here and elsewhere where others tell owners to not use Mobil I )
6. improper maintenance and oil levels.
7. etc

Point being lots of claims and if "don't care" of all the above then that would leave valid failure points fairly low.

What we do know is for the first time starting with LS7 is GM had to put in writing that if PCM is tuned then take a hike which says they see most failures as to the hacks and mods which clouds what the real failure rate is

Add the hype from changing valve springs often to All LS7s having bad rockers only confuses even more what the real failure rate is and GM cannot get that when most LS7 failures were due to crap mods and tunes to prevent getting the true Mean Time Between Failure (MTBF) rate

If the heads flaw was real high GM would not be selling LS7 as crate engines and now using it for 2014 Camaro Z28
 
#38 ·
Any of you "suckers" who bought an LS7 powered car should dump them for pennies on the dollar. Please PM me to dump your POS car!! :lol:
 
#39 ·
So I started following the "valve guide wear" chronicle a while back, then lost interest since I don't own an LS7 engine. Is GM still being strategically vague about this issue? Or have they issued an official recommendation for those owners out of warranty? Something like, "this is what you should replace...".

I guess it's not in their best interest to do that, is it? That would be like admitting there was a problem in the first place. And I really don't think they want to open themselves up to further liability.

I certainly understand how this can be a frustrating situation for C6Z owners.
 
#40 · (Edited)
Let's get to the bottom line. How can you definitely tell if you have a valve guide problem. Other than hearing a ticking noise which could be from another source is there a way to check for this? I'm looking for a test that may be something like taking off the valve spring retainer and spring and checking play between the stem and guide.
 
#41 · (Edited)
Ticking is one of the indicators there is a problem. Another pull all the spark plugs and check for oil around the the threads. If the valve is moving beyond specs. the valve stem seal will leak oil past it and show up on the plug threads. You really need to check all the plugs as some may not show the problem. But the sure test is take it someone and check the valve movement with a dial indicator or similar tool.

PS Mine is an early production date 2008 with 19K miles. Had the valve guides checked today and they are all within tolerance. So not all are bad as some are trying to say on the other forum. But for peace of mind, I recommended checking them.
 
#42 ·
Hi guys, I just dropped my 2008 Z06 off at a dealership here in Phoenix for this issue (I think.) The sound started abruptly last Tuesday and the car got promptly garaged. I finally got a chance to take it in this morning and the dealership pretty much went straight to the valve train. When I came back to grab my garage remote, the mechanics had the left valve cover off of the engine and had pulled the number 6 rockers off. The service advisor guy told me that they would more-than-likely pull and rebuild both heads and possibly change the camshaft. I bought the car used and bone stock, with 9800 miles on it and it had approximately 18,400 miles on it when this problem manifested. The only modification to the vehicle is a Calloway Honker CAI. To make this reply relevant to the thread's title, I have to say that so far at least, the dealership seems to be working with me and I'll report back on the outcome. Hopefully everything goes smoothly and no warranty or other issues develop.
 
#45 ·
The only modification to the vehicle is a Calloway Honker CAI. To make this reply relevant to the thread's title, I have to say that so far at least, the dealership seems to be working with me and I'll report back on the outcome. Hopefully everything goes smoothly and no warranty or other issues develop.
Please keep us posted. With only a Honker intake you should be okay regarding warranty issues. If you have any problems, please do not hesitate to PM me.
 
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