I'm about to replace my IPR and my thermostat, and just watched a video saying after replacing the thermostat you need to bleed the air out of the system to get rid of air pockets so you don't overheat the engine. Is this true and if so how do you do it? Also, how much coolant do I need to drain before taking off the upper radiator hose?

 

I plan to replace the thermo myself. Great question about bleeding the coolant system. Thought I'd give you a bump OP.

 

2-3 gal of coolant drained should drop it low enough to change tstat. To bleed it, fill it up, leave the cap loose & let it warm up to operating temp. Tighten cap, take it for a drive & get rpms up. Tow/haul mode will help keep rpm up. You want that water pump pushing a lot of volume to rid the air. Might take a few days/drive cycles to completely burp it, carry coolant with ya for a week after & check it regularly.

Edit: put heater on while running to bleed heater core of air