Today I had a VY Commodore in Elanora with the compliant of leaking coolant. A quick pressure test of the cooling system showed the leak. The water pump was leaking coolant out of the weep hole. This means the shaft seal is leaking coolant and its time for a new water pump. On this vehicle its a very straight forward job as access is easy. On other vehicles with timing belts it can be a much larger job as the water pump is usually driven by the timing belt. Meaning a lot more labour to carry out the repair.
In the pic you can see the old and new pump together. The 2nd pic shows the weep hole where the coolant was leaking from. The cause of the failure was from the bearing on the shaft wearing out and causing movement which damaged the seal.
Once the new pump was installed the coolant is refilled. Then its very important to bled the cooling system to remove any air from the system. Finally I re-pressure test the system to ensure the repair has work and that no other leaks are present.