- 1). Locate your Mazda's radiator. It should be the first thing you see when you open up the hood.
- 2). Place a drain pan on the ground directly underneath the plug for the radiator by laying on the ground with your head underneath the radiator.
- 3). Remove the drain plug for the radiator. You may need to unscrew or at least loosen the screws to get the plug to come out. Coolant will flow out immediately, so be sure to move out of the way.
- 4). Pour distilled water through the radiator cap on the top of your Mazda's radiator to ensure all of the old antifreeze drains out. Distilled water is best, but you can use regular tap water if necessary.
- 5). Replace the radiator plug once it has stopped draining. Affix tightly and ensure any screws are tightened down.
- 6). Refill the radiator on your Mazda 3 from the top. Fill the reservoir next to the radiator as well.
- 7). Put the radiator cap and the reservoir cap back in place, ensuring they are on tight.
- 8). Run your Mazda M3's engine for 10 to 15 minutes, watching the temperature gauge to ensure the coolant is running through the engine correctly. If the temperature gets hot, turn off the engine.