Sound only at low speeds / 1500 RPM

Hi, my name is Devin. I am an auto repair expert with the Car Genius team here at RepairPal. So sorry to hear you're having trouble with your vehicle. The whirring sound you're hearing around 1500 RPM might be caused by something minor, like a resonance in the exhaust system or a pulley in the belt system. Since it's a certified pre-owned vehicle, it's still under warranty, and you can insist that the dealer investigate further. Even if the dealer said it's nothing to worry about, your peace of mind is important. Try documenting the issue, and maybe ask them to check for any loose components or wear on belts and pulleys. If they are unwilling to look into it, visiting another Mercedes-Benz dealer may be the next best thing. If you need more advice, have any other questions about your vehicle, or would like to get connected to a RepairPal Certified shop near you, we have you covered. Give us a call at 877-913-1554, and we will happily help you out!