I’m hearing a popping sound similar to a plastic bottle popping coming somewhere from the back seat of my Volvo XC70. This usually occurs while driving a few miles after first starting the vehicle and happens only once. We’ve check the car for any plastic bottles that may have been lodged under the seat or inside the car and no bottles were found. We wanted to find out if anyone else is experiencing this same sound as we have no idea why or where it is coming from. There seems to be no mechanical problems associated with it, just this popping sound which is quite loud.
Take it back to the dealership and have them look it over. If they give you the “it’s normal” spiel, ask them if you can test drive another XC70 on the lot to see if it does it too. You may have to leave it overnight so the tech will have a better chance of finding the noise.