Just look carefully at the tensioner for any signs of oil leakage. Volvo says that if it leaks, replace it otherwise it should be OK. The ONLY exact way to know how well it's still holding proper tension on a higher mileage engine is to use a special ($500) Volvo tool that measures T-belt tension prior to removing the old belt. In my experience, I have yet to see anyone ever doing that nor have I seen a bad tensioner that wasn't leaking oil (IE: no belts breaking/slipping after the fact). As for the water pump, look at it for signs of leakage. Some crust from seapage isn't unusual nor would I let that alarm me. Spin the pulleys to make sure they feel, sound OK as they're usually not a problem.