The dealer has determined that I need to replace the catalytic converter at a cost of $1200 plus tax. I am two months out from my power train warranty and 15,000 miles over my emission warranty, so neither warranty applies. I told them I would get a second opinion from an independent muffler shop since their price is so high. The first phone quote I got was $289. plus tax from a shop a mile away from them.

 

If anybody needs an example of why it pays to shop around, just pay attention to the quote above, $1,200 vs. $289.

 

I took the car to the muffler shop. They initially found a resonator that was rattling, and replaced it for $100. Unfortunately, that didn't fix the problem. They then were able to reproduce the problem with the car on the rack, when someone pushed down the gas pedal. However, they couldn't isolate its exact location while the exhaust system was warm. They are keeping the vehicle overnight, and will resume diagnosis tomorrow morning after it has cooled off.

 

Might even be a heat shield resonating on you, they can vibrate in sympathy with the exhaust and really create a ruckus.

 

The muffler shop couldn't recreate the problem today, even with the cold exhaust system. They said there is nothing else to fix now. I picked HHR up and it still makes some of the noise, but not as loudly and it requires deeper pushing of the gas pedal to initiate it. Still normal performance and no check engine light or other abnormalities. They said it absolutely does not need catalytic converter replacement.

Cost: $50 plus tax for the local dealer to diagnose it wrong (Red River Chevrolet Bossier City, LA) on 2nd visit, 2 1/2 hours of time (but no money) wasted there at first visit. $105 ($90 plus tax and shop supply fee) for replacement resonator, which they did while I watched, at the muffler shop.

Cost avoided: $1200 plus tax for dealer recommended catalytic converter replacement.

Lessons learned?

 

Good deal man. Glad it worked out for you. Seems like treating yourself to a steak dinner tonight would be a nice way to give yourself a pat on the back.

 

H'mmm, I just looked at Rockauto.com under 2007 HHR 2.4L exhaust & emissions did not see a resonator listed. New Catalytic converters start at 179.99 and may include the gaskets. I have personally done the job laying underneath the car on jack stands in 1 hour and 1 beer (including jacking up/down), it is a total of 5 nuts & bolts/studs and 2 HO2 sensors (those connecters are tuff). In Texas, I would not expect any more corrosion than I saw in DC, I did not really need the WD40.

I did see something called "Exhaust Manifold Bypass Gasket", no clue what that is.

Also to check the tightness of the bolts/nuts, gaskets, HO2 sensors.

 

I checked in with the service writer today and found out something quite interesting. The technicians probably diagnosed the problem correctly as the resonator. Being a GM dealership, the only way they are allowed to replace the resonator is to replace the entire catalytic converter assembly, of which the resonator is a subset. Consequently, they reported the only way they could: bad catalytic converter. She said another customer today had a bad "Y pipe" portion of the catalytic converter which also could be replaced separately and for some reason wasn't even covered under the emissions warranty. Again, the only dealer choice is to replace en bloc. Service writer actually suggested that customer go to an independent shop for a second opinion. That customer insisted that all her work be done at the dealer, so she's paying the cost for a full replacement.

 

I apologize for my confusion. What is the outcome of your situation with your vehicle? Are you going to have to pay to have this resolved or are they going to figure out a way to get this covered?

According to the information I have available to me the Catalytic Converters and powertrain control modules should be covered for the first 8 years or 80,000 miles, whichever comes first.

Michelle, Chevrolet Customer Service

 

Good morning Michelle. Read his post #21. Unfortunatly it looks like he is outside of any warranty coverage.