Tomorrow I will be changing my cars thermostat, do I have to bleed the coolant?

Do I have to bleed the antifreeze coolant, it is about 80% full.|||Depends on your car some come with bleeders some don%26#039;t. I usually don%26#039;t mess with it unless I cant put the same amount of coolant in that I took out. I assume thats what you are asking. If you are wondering if you need to drain the coolant yes you do.|||Yes, unless you want a major spill on the ground.|||no you don%26#039;t|||you should bleed it because there will be air in it. just start it up and pull 1 of the heater hoses off for a second then put it back on.