Abstract: A water pump, especially for the cooling system of a combustion engine of a car, has a housing with a space for a fluid. This space contains a pump device. The pump device is mounted on a shaft which projects form the housing. The shaft rotates while being supported by a bearing assembly. The bearing assembly has an outer stationary ring mounted on the housing. The fluid space id sealed with respect to the shaft by a sealing unit having a first ring connected to the shaft, and a stationary second ring mounted on the outer ring of the bearing assembly. The first and second rings have sealing surfaces which are directed toward one another, or extend axially. The first ring is resiliently biased toward the second ring, to provide a seal therebetween. The first ring is connected to the shaft via an elastic dampening and centering element located between the inner circumference of the first ring and the outer circumference of the shaft, and distributed over the circumference of the shaft.