Help! Catalytic converter, intake gasket etc

[Robk]

I have a 2007 corvette with 30,000 miles. Purchased new in November 2006. Since I have owned the car I have had 5 catalytic converters replaced. This last one occurred 1 month past the 8 year warrany mark. I have not been able to get any answers from service dept as to why this is happening. Each service rep says they have never seen this before. They call and talk to GM tech reps but still no answers. I spoke with the general manager who, at least, was able to get me the part for free, but I still had to pay for the labor. His explanation was that the catalytic converters were basically junk but that the newer replacements should be better. I guess only time will tell. This last time they also found a faulty intake gasket....again, I would not expect this in a car with only 30,000 miles. Dont even get me started on the harmonic dampener I replaced less than a year ago that already is making noise again.
Anyone have any insight into these issues?

 

[LLC5]

I have a 2007 corvette with 30,000 miles. Purchased new in November 2006. Since I have owned the car I have had 5 catalytic converters replaced. This last one occurred 1 month past the 8 year warrany mark. I have not been able to get any answers from service dept as to why this is happening. Each service rep says they have never seen this before. They call and talk to GM tech reps but still no answers. I spoke with the general manager who, at least, was able to get me the part for free, but I still had to pay for the labor. His explanation was that the catalytic converters were basically junk but that the newer replacements should be better. I guess only time will tell. This last time they also found a faulty intake gasket....again, I would not expect this in a car with only 30,000 miles. Dont even get me started on the harmonic dampener I replaced less than a year ago that already is making noise again.
Anyone have any insight into these issues?

That is not normal, 5 cats in 30K miles. 1) Who has been doing the diagnosis, and 2) what codes were stored to support that the vehicle had a bad catalytic converter?

Also, any mods to the vehicle that are not OEM or GM?

 

[Robk]

Cat converter

All the work except the harmonic dampened has been done by chev dealer. Just checked my records. Has been four not five converters but still four too many. No modifications done to the car. Do not know the specific codes that were displayed. Only one if the receipts says which side was replaced. I know at least one on each side. The last service rep said something about there being three cat converters on the car but I thought it was just one on each side.

 

[LLC5]

All the work except the harmonic dampened has been done by chev dealer. Just checked my records. Has been four not five converters but still four too many. No modifications done to the car. Do not know the specific codes that were displayed. Only one if the receipts says which side was replaced. I know at least one on each side. The last service rep said something about there being three cat converters on the car but I thought it was just one on each side.

Without knowing the codes that were thrown to support a bad cat diagnosis, it is impossible to know why someone replaced it. In my experience the most common cause of cat failure is coolant in the combustion chamber, but it is rare. Catalytic converters since the late '90's are extremely efficient and durable if they are OEM but of course there are small exceptions at times, but not four or five on one vehicle in 30K if they were OEM cats. If they were aftermarket cats, then maybe.

Are you the original owner of the vehicle, and did you buy it from the dealer that is now doing the work?

 

[c4c5specialist]

HI there,

Well, as LLC5 has stated, without any diagnostic trouble codes or symptoms to determine failure, theory is all you have.

#1, OEM converters when they fail, there is ALWAYS a reason behind it.

#2, I have NEVER EVER had a converter fail from GM without something CAUSING IT.

#3, if a lower quality fuel is used, converters can be coated and loose correct function.

#4, top tier fuels can always help you, HOWEVER, OCTANE is only PART of the formula.

If it was me, I would suggest FIRST to have an accurate diagnosis done. Evaluate any aftermarket components, if there are any, on the vehicle. RE: aftermarket oiled air filters are a HUGE ISSUE for converter failures.

Request printouts of scan data to determine root cause.

Allthebest, Paul

 

[Robk]

Catalytic converters

Thank you both for your interest and help. I purchased my corvette new from the dealer in Nov 2006. All the work, except the replacement of the harmonic dampener 1 1/2 years ago, was done by the original dealer. This is my every day driver but I have a short commute hence the low miles, 29,000. I use only premium fuel and no additives. I had misplaced my early receipts so had the dealer copy them for me. I actually have had 3 right and 4 left converters replaced. Here is a summary as best as I can tell from the receipts.....July 2007, 5,100 milesDiag code P4020. L2300 A4 Diag, A6 Failure code. Replaced Bank 1Oct 2008, 9,000 milesL2300 A2 replace Right Bank, A4 replace left bankNov 2011, 17,300 milesDTC P4030, Test exhaust with smoke and found leak in welding before post oxygen sensor. Replaced bank 2Jan 2012, 17,900 milesDTC P4020 Bank 1. No misfires, no high oil or coolant consumption. Damaged oxygen sensor wire harness. Replaced post oxygen sensor bank 1 and 2. Fuel composition test 9.5%. Reprogram PCM in mode new. Performed crankshaft position variation relearn procedure, DTC resets again. Check crankshaft sensor due to PIP. Removed starter assembly to check crankshaft sensor connector. Retest cat converter bank 1 fails again. Replaced ECM reprogram....(there was another page that was not faxed to me.....replaced J6372 sensor,oxygen(engine control). Replaced J6380 heated oxygen sensor. Replaced L2300 cat converterJun 2013, 23,780 milesDTC P0420 bank 1, replaced left converterDec 2014, 29,000 milesCat converter internal failure 4050900 code P0430. Replaced bank 2. Also vacuum leak intake gasket...replacedAs I mentioned earlier,as the car is no longer under warranty and they wanted to charge me for repair, I spoke with the dealer general manager. His response was that the catalytic converters were made poorly. From what you are saying, and I agree, this should not happen unless there is something else wrong with the car causing these failures. Seems the dealer may be blaming the probblem on faulty cat converters rather than a faullty car and their inability to find the problemAgain, appreciate any feedback you have. Happy new year!ThanksRob

 

[c4c5specialist]

Hi there,

According to that information, its not the same converter. They replace both sides, oxygen sensors and other things.

I can definately relate to some of this, but it is NOT the same converter every time.

You went 3 years between converter changes and I can tell you first hand, fuel formulations have changed dramatically over these years.

also, premium grade fuel means nothing if its bought from a no named station or one that is not from a 'top tier' manufacturer.

Top Tier Gasoline for further information on this recommended fuel formulation and those who make it.

Honestly, the theory that these converters are made poorly, I disagree with.

Allthebest, Paul

 

[Robk]

Catalytic converter

Thanks Paul. 90+% of the time I use either Shell or Chevron. Occasionally use Arco or Costco. To me, the fact that it is both converters makes me more suspicious there is an underlying problem with the car. My fuel purchasing habits are no different than they have ever been and I have never had a car that needed a cat converter replaced once, let alone 7 times. I have never talked to anyone else that has needed one replaced on a car either.
Any suggestions on someone or someplace at GM I could call to discuss this with? I probably shouldn't have waited this long to do it but it didn't bother me as much when warranty covered it.
Rob

 

[LLC5]

Thanks Paul. 90+% of the time I use either Shell or Chevron. Occasionally use Arco or Costco. To me, the fact that it is both converters makes me more suspicious there is an underlying problem with the car. My fuel purchasing habits are no different than they have ever been and I have never had a car that needed a cat converter replaced once, let alone 7 times. I have never talked to anyone else that has needed one replaced on a car either.
Any suggestions on someone or someplace at GM I could call to discuss this with? I probably shouldn't have waited this long to do it but it didn't bother me as much when warranty covered it.
Rob

You can contact GM customer service, it should be a toll free number in your owners manual, they can look up your history and advise how to proceed. Good luck with it.

 

[Robk]

Catalytic convereter

I contacted GM last week. Must admit I did not expect to get any significant help but the rep really did sound like he wanted to help. Heard back within two days. After reviewing the service history GM wants to buy the car back. Not sure yet what kind of offer they will make. Car is 8 years old but still has very low miles and prob started at 5100 miles. After all the problems I had with the car was thinking I would not get another vette but if GM comes through and makes things right, that would go a long way to keeping me a loyal vette owner. I was certainly hoping to keep this car another 4-5 years til I'm done paying off my kids college costs before taking on another car payment. Hopefully GM will make it easy for me.

 

[LLC5]

I contacted GM last week. Must admit I did not expect to get any significant help but the rep really did sound like he wanted to help. Heard back within two days. After reviewing the service history GM wants to buy the car back. Not sure yet what kind of offer they will make. Car is 8 years old but still has very low miles and prob started at 5100 miles. After all the problems I had with the car was thinking I would not get another vette but if GM comes through and makes things right, that would go a long way to keeping me a loyal vette owner. I was certainly hoping to keep this car another 4-5 years til I'm done paying off my kids college costs before taking on another car payment. Hopefully GM will make it easy for me.

Wow. Did not see that one coming on an 8 year old vehicle. I thought they may offer some goodwill warranty, but I never even considered a buy back at this stage. Hopefully their numbers work for you.

Way to go GM!