Not sure if the pump is driven off the cambelt, but if the water pump is driven off the cam belt then yes do cam belt tensioners might as well do the aux belt to as it has to come off in the process.
Astra-J 2.0 CDTI S/S
Retrofitted AFL, TPMS, Navi950, BT, DAB, Rear Camera, Infinity sound system, Towbar, Flexfloor & more.
I can do programming and retrofits using genuine GM MDI and Dealer software.