Weak points in coolant system?

[jkdjim]

Within the last year, I had a coolant leak that my Volvo guy determined to be a cracked coolant reservoir. Fast forward to this weekend I get the coolant low warning, top off, and then yesterday it's back below the minimum line with the corresponding warning. Assuming the reservoir is fine, what are the likely culprits of a leak in the system before I take it into my Volvo guy? Water pump? Radiator? Flux capacitor?

For what it's worth, I have about 140k miles on the clock. Might be time to do the timing belt again (not quite sure when it was done before but didn't look too bad when I changed plugs). I've heard it's good to swap water pump when changing timing belt, correct?

[Eldoninoz]

I had the 10 mm line from the top of the radiator to the reservoir crack and leak on me, as the pressure built it blew on a road trip, could go about 50 miles or so between topping the reservoir off. May want to check it.