Water pump diagnosis?

[AlanS]

Im trying to narrow down a dash message on my 2013 T5 S60- "High Engine Temp"- See manual. OK, how do I know if the WATER PUMP is working? In the 'ole days' you would open up the radiator cap when the engine was hot...rev the engine....water should circulate. How do I do this on a closed system like ours? My only port is the expansion tank/ reservoir. Aside from the water pump...I realize it could be the fan (which does operate if I turn on the A/C), thermostat or sensor. Really want to approach this methodically, and save as much time and $$$ as possible.

[jderimig]

Water pump impeller not spinning and stuck closed thermostat will give the same symptoms I think. I don't think you can pinpoint either alone with a radiator temperature or flow check.