Support and repair guides for the 2002-2008 Mazda 6. The first generation of the Mazda 6, also known as the Mazda6 and the Mazda Atenza (in China and Japan).
Eduardo Acevedo P0128 should be a coolant thermostat stuck open. check this site for more information. Could be just a matter of flushing your coolant system and replacing the thermostat.