How to Change Antifreeze in a BMW 525I

1. Park the 525I on a level surface. Raise the hood and let the engine cool. Remove the radiator cap. Place a large drain pan beneath the radiator drain plug on the passenger side of the radiator.
2. Unscrew the radiator drain plug. The plug protrudes from the radiator enough that you can unscrew it by hand. Drain all of the coolant into the drain pan.
3. Tighten the drain plug by hand. Remove the drain pan from under the car. Fill the radiator with a 50-50 blend of antifreeze and distilled water.
4. Start the engine. Let it idle until the engine warms up. Add coolant to the radiator as needed when the level drops. Turn the engine off once it warms up, then let it cool. Top off the coolant in the radiator if needed.
5. Replace the radiator cap and close the hood.