The noise we are hearing is like someone blowing into an empty drink bottle. It's not a steady noise. Definitely not a wheel bearing. It sounds as though there is no sound insulation in rear of car. Noise does not change with road surfaces. Dealer has changed the tires from Continental to Michelin. Dealer states that this is a characteristic of the car. That is BS. Just rented and drove a 2018 Chevy Malibu to Florida and back 1800 miles. (NO NOISES). Have driven other vehicles similar from Dealer inventory with no noise. Chevy states they have no complaints about this. I guess they are not reading the Chevy Malibu Forum or just don't care. I will not go away until this is repaired or they replace the vehicle.
Update from Oct 8, 2018: I have added insulation to the trunk area to no avail. The sound does get worse depending on road surface and it is loud. You can hardly hear radio. The car I drove to Florida was just a Malibu and not a Premier. That car had P215 55 R 17 tires and 17" rims. The only way I can diagnose this noise is to rent a base Malibu with 17 inch rims and tires, bring it back to my shop and swap rims and tires between vehicles. If there is no noise, problem solved. I truthfully believe the 19" rim size in conjunction with the P265 40R 19 tires are creating the noise due to the with of the tires and the volume of air in them. The volume of air is magnifying and amplifying the contact with the road surfaces transferring the noise to the passenger compartment. By going up to a P235 55 R 17 tire and rim it only changes the speed by 1 mph at 80 miles per hour up to 100 mph. I will let this site know the results of my findings. If you are experiencing the same problem please report it to GM by filing a complaint.
The noise we are hearing is like someone blowing into an empty drink bottle. It's not a steady noise. Definitely not a wheel bearing. It sounds as though there is no sound insulation in rear of car. Noise does not change with road surfaces. Dealer has changed the tires from Continental to Michelin. Dealer states that this is a characteristic of the car. That is BS. Just rented and drove a 2018 Chevy Malibu to Florida and back 1800 miles. (NO NOISES). Have driven other vehicles similar from Dealer inventory with no noise. Chevy states they have no complaints about this. I guess they are not reading the Chevy Malibu Forum or just don't care. I will not go away until this is repaired or they replace the vehicle.
Update from Oct 8, 2018: I have added insulation to the trunk area to no avail. The sound does get worse depending on road surface and it is loud. You can hardly hear radio. The car I drove to Florida was just a Malibu and not a Premier. That car had P215 55 R 17 tires and 17" rims. The only way I can diagnose this noise is to rent a base Malibu with 17 inch rims and tires, bring it back to my shop and swap rims and tires between vehicles. If there is no noise, problem solved. I truthfully believe the 19" rim size in conjunction with the P265 40R 19 tires are creating the noise due to the with of the tires and the volume of air in them. The volume of air is magnifying and amplifying the contact with the road surfaces transferring the noise to the passenger compartment. By going up to a P235 55 R 17 tire and rim it only changes the speed by 1 mph at 80 miles per hour up to 100 mph. I will let this site know the results of my findings. If you are experiencing the same problem please report it to GM by filing a complaint.
- Stephen F., Lanesville, US