How to Change Radiator Fluid

The radiator fluid within your vehilce will need to be changed as part of regular maintenance. This will prevent the engine from overheating . If you notice that the fluid is rusty while you are changing it, then you will need to get your system power flushed and changed.  Learn how to change the radiator fluid properly to ensure your safety and to prevent a trip to the mechanic.

Things You’ll Need:

• Bucket


• Box wrench or socket wrench


• 50/50 or 100 antifreeze


• Rag

Step 1: Change fluid when the engine is cold to avoid injury. Cool the engine for at least five hours before attempting to change the radiator fluid.

Step 2: Place the bucket under the radiator drain plug.

Step 3: Wipe any dirt around your radiator cap, then unscrew it a quarter turn to release any built up pressure. Remove the cap completely once the sound and fluids stop – turn it counterclockwise.

 Step 4: Drain the radiator system by loosening the radiator drain plug. In most vehicles, the drain plug can be loosened by turning a bolt on the bottom of the radiator.

Step 5: Watch the fluid as it flows out of the radiator. If the old fluid is brown, or it appears dirty, take the vehicle to a shop to have the system power flushed.  

Step 6: Bolt the plug back into its place with the socket or box wrench.

Step 7: Fill the radiator back up with 50/50 or 100 antifreeze, and then firmly screw the radiator cap back on again.

Step 8: Start the engine and let it run for 10 minutes to watch for signs of the vehicle overheating. Check the radiator fluid level again if the engine gets to hot within the first five minutes – do not check the fluid until the engine cools off again.

Make sure you always put the correct mixture of antifreeze back into the radiator system when you change out the radiator fluid. If the antifreeze is mixed incorrectly, or plain water is used, the engine can sustain serious damage. Find the mixing instructions on the bottle of antifreeze – they will vary according to brand.