Exhaust fumes and soot accumulate on rear bumper marring paint and may cause other problems I.e. monoxide. Have attempted to get it fixed at three dealers but they claim it's nothing and simply wash soot off.

- Denver , CO, USA

There is heavy black carbon buildup on the tailpipes and rear of my Azera. The Hyundai dealer said it is normal due to the type of catalytic converter they use. My Lexus mechanic (our other car) said it probably a problem with the fuel to air ratio the car is using.

- Newport Beach, CA, USA

I purchased a new 2013 Hyundai Azera. My wife and I was given a class on our new vehicle. The day of our purchase my wife and I noticed the back bumper was every dirty, we thought. The back bumper was covered with black carbon that came from the exhaust that also had carbon as well inside and around the outside tips. I contacted the dealership where we purchase the car. They ask what grade gas did we put in the car" I explain that we would not put fuel in the car and that they filled the car with fuel. And explained that we had just left the dealership a few hours ago. Service asked us to put 87 octane in the next time we fill up. I called Hyundai company and they said to use 87 octane fuel as well. I understand pump gas has additives that are added to gas. I've only seen this with gas vehicles that are running bad or with problems and diesel engines powered vehicles. Do U.S. department of transportation have anything on a Hyundai's 2013 Azera"

- Nc, NC, USA