A sealing device comprising a sealing ring (31) for being accommodated in a groove (11) of the first machine part (10). The sealing ring has a sealing surface (32) for contacting the second machine part (20) and an annular groove (33) in the sealing surface with sealing surface portions (32a, 32b) on respective sides of the groove. First and second opposed sides (35, 36) extend transversely to the sealing surface. One or more bores (37, 38) establish fluid communication between one or both opposed sides and the annular groove in the sealing surface. An O-ring (34) is arranged in the annular groove and seals the bores on the low pressure side of the sealing device.
