The humpback of the stove is a common problem in Polo Sedan. Most of the time, it is in the cold, on the unsoaked machine. The reason for the noise is in the tulk bearings of the slide. Over time, dust gets there, there's no grease, and it starts to make a whistle.
Official dealers usually solve the problem by replacing the electric motor with the wing during the warranty period. It also helps to lubricating the electric motor, but the effect does not last long.
