Water pump and coolant tank replacement?

[GranburyChuck]

Hey all, 2000 996 C2 Tip with 102k miles. Noticed a slight turbine sound over last couple of weeks. Not just at start up. Matches engine RPM w/ or w/o transmission in gear. Listened to the engine running but couldn't audibly locate it. So I suspect a pulley somewhere on the engine. Anyway, I was thinking that maybe I should do some preventative maintenance on the moving parts. So I was thinking of changing the water pump and coolant tank. No signs of leak that I can tell and temps seem to be okay. Since I live in a rural area my main concern is having a failure then being stuck. So I look up parts on the internet and find them for about $600 (w/p, gasket, thermostat, coolant tank, new cap, some rad fluid, polyrib belt). Read DIY on W/P and coolant tank. Although kind of a PITA, doable. Dealer said $980 for W/P and $730 for coolant tank but DID NOT recommend I do this unless I am seeing it leak.

Thoughts? DON'T fix what isn't broken or FIX it before it lets you down in BFE!

[win911]

You might also want to check the Alternator since that too has a moving pulley that could also cause the sound you are refering to. With 102k miles and living in a rural area....why not. I would change it since it is not that hard to do anyway. Good luck.

[GranburyChuck]

You might also want to check the Alternator since that too has a moving pulley that could also cause the sound you are refering to. With 102k miles and living in a rural area....why not. I would change it since it is not that hard to do anyway. Good luck.

Turns out it is the alternator.