Thought I would put this out there for future searchers who are hearing noise from the vicinity of the water pump. Check your AC idler pulley first, if you have one.

The external heater core to engine hose sprung a leak on my 1976 280Z and sprayed half of the coolant out as I drove home one night. I replaced the hose, refilled with coolant, then soon after (days), I started hearing what sounded like bad bearings from the front of the engine.

I thought for sure that my water pump bearings had cooked themselves after the hose had burst. But before I got too deep in to it, I remembered that my AC idler pulley had made some noise in the past, fixed at the time (apparently temporarily) with a drop of oil and some WD-40. I took the AC belt off and was back to quiet running. Winter's coming and it need charging anyway, so it's a spring project now.

Just putting it down for the record. It's easy to loosen the AC idler pulley and remove the belt, to see if that's the source of the noise.

FYI, you can rebuild that pulley. Motorsports Auto sells the bearing.

as well as several other places.......

Thanks for reminding me. I do remember reading some posts about that, with descriptions of the bearings that would work. I'll search it out.

You're probably referring to this thread.