BMW Repair: 528i BMW blown coolant reservoir, upper radiator hose, light car

Question
Own a 528i BMW with about 144k miles, last 7 of vin BW33406. Just was taking a trip in the mountains and came to intersection and got stuck at traffic light.  Car overheated and was able to pull over very quickly (within a  1/4 mile).  Only on the red for less than a minute.  Problem appeared to be that the coolant reservoir split down the side.  We epoxied and duct taped it and refilled and were able to get down the mountain fine with no more overheating.  My question is do you think replacing reservoir and pressure cap is the solution or could there be a problem with the water pump as well (how to tell?).  Wondering how to proceed as have bought reservoir and cap (($100) and would hate to have it blow again because we have not replaced water pump or something else.  Thanks much for your help in advance.  PS I do not believe the water pump has been replaced previously.

Answer
Randy, Good to hear you caught it early. If the car hasn't had coolant work before and all parts are original, I would change the water pump, Map thermostat (above pump), and upper radiator hose. Radiators have a tendency to crack at the upper radiator hose neck so be careful. BMW's down side is using too much plastic in the cooling system.
After being heat cycled hundreds if not thousands of times they get very brittle.
-Evan