I am planning to replace a water pump including serp belt and pulleys.
for pulleys, 2x idler pulley and 1x tension pulley. Is the tension pully and idler pully same size or differnt?
when a water pump replacement, is there any other parts to replace?
1. water pump 2. serp belt 3. 1x tensioner pulley 4. 2x idler pulley

My car is 2009 RX350 AWD 140k miles

Replace the coolant thermostat.

Thank you, will do.