Don't bother replacing the water pump.

I cannot remember a single post, since I have been on this board, concerning an 850 water pump failure. They just do not occur on low-mileage cars. Past 140K, or 210K, maybe, but not at 65K.

The likelyhood that the mechanic changing your water pump accidentally, strips a bolt, or doesn't tighten the bolt correctly, or doesn't replace the 'o-'ring/gasket, or forgets to put a bolt in, or uses a cheap replacement pump, etc., etc., etc. . . . is far more likely that a water pump failure.

Although water pump replacement, on cars with chronic water pump failures, is a good idea, this is one of the few Volvo parts which appears reliable. So, leave it alone.