NHTSA Complaint #11685679 — 2020 GMC ACADIA

I'm not sure of the exact sequence of events here, but there are multiple exhaust leaks. One is a crack somewhere in the catalytic converter that is now leaking exhaust from the back of the engine into the passenger compartment. The other leak is at the point of a bracket which fastens the two front exhaust pipes together. At the time we first noticed an exhaust leak sound upon cold start, there were are around 58,000 miles on the car. Now a month later there are still less than 60,000 miles on the car. The dealership originally estimated repair costs to replace the catalytic converter and two front pipes at $3,200. When I had another service garage look at the problem, they asked why the GMC dealer wasn't willing to replace the catalytic converter under the 80,000 mile / 8 year warranty. When I raised this with the dealership, they said this was a "gray area" becasue they believe what happened was that the exhaust bracket at the front pipes failed first, which then caused the catalytic converter to crack. Ultimately, they indicated they would be willing to pay parts and labor related to the catalytic converter (approx $2,000) if we paid the other $1,200 to cover the front pipes. What I don't understand is why, when both Chevrolet and Buick have extended their front pipe warranties on comparable model years of the Chevy Traverse and Buick Enclave, which use the exact same part numbers for the catalytic converters and pipes to 150,000 miles/15 years, why GMC has not offered the same special coverage on the Acadia. Regardless of which cracked first, the front pipe bracket or the catalytic converter, there is likely an engine vibration/movement issue that casues the cracks, giving rise to exhaust venting into the passenger compartment. Since we have yet to be able to schedule the repair (catalytic converter was on back order), we can now only drive the vehicle with the windows down to lessen the exhaust smell. The Acadia deserves a Special Coverage Advisory on this.