Bleeding a radiator on a Peugeot 405 is necessary after you've flushed the system. Air can get trapped in the system and that can cause problems with the water pump and cooling cycle. To purge the air, you'll need to bleed the system.
Allow the engine of the Peugeot to cool completely after running.
Jack the front end of the Peugeot off the ground using the front jack point, located behind the radiator.
Push down on the radiator cap on the top of the radiator and twist it counterclockwise to remove it.
Note the coolant level. Start the engine and allow it to run until it reaches normal operating temperature. As the coolant cycles though the system, any trapped air will be forced up and out of the vehicle through the open radiator cap. Periodically check the coolant level. As it falls, this will be an indication that the trapped air has been released. After the vehicle warms up, all, or most of the air should be bled out of the system after roughly 15 minutes.
