Thermostat replacement on a Mazda 3 - P0126

Showing how to replace the thermostat on a Mazda 3. The thermostat in my car was stuck in the open position, causing the engine to warm up slowly. This is especially problematic in the winter time. In order to get to the thermostat it is best to first remove the belt tensioner. Do not forget to collect the old antifreeze and dispose it appropriately. Antifreeze is harmful to the environment. So it is best to give it to a recycling center close to you.