The i.c. engine cooling water pump has a bearing cover secured to the housing, in which is mounted the pump shaft with an impeller in a bearing. A seal between the bearing cover and shaft is mounted between the impeller and bearing, while there is an annular chamber with air vent between the bearing and seal. Several passages (8, 9) through the bearing cover are situated on opposite sides of the shaft (4). In the space between them and the bearing (5) is an absorbent ring (10) fitting round the shaft.
