Where can I found the breather for the coolant.

There is no breather, if you want to bleed all the air, run the engine with the heater open, and tape a plastic bottle with the bottom cut out up side down into the coolant filler, keep a head of water in the bottle until thermostat opens and system should bleed all air, there is a special tool designed for this but the bottle works well if you can keep the radiator end sealed and keep water level up in the container.