The Toyota 4Runner is a full-sized SUV that has been in production since 1984. The antifreeze in a 4Runner helps diffuse the heat from the engine. Because it has a higher boiling point than water, the antifreeze holds up better under extreme conditions. The type of antifreeze used in the 4Runner will vary depending on the model year and engine in the vehicle. Consult the owner's manual before changing the antifreeze for instructions on which antifreeze to purchase.
Park the 4Runner on a level surface and set the parking brake. Allow the engine to cool for 30 minutes.
Open the hood and secure it in place with the hood prop. Open the radiator cap to release pressure on the coolant lines.
Place a bucket under the radiator drain valve. Remove the valve with a socket wrench and let all of the coolant drain into the bucket.
Pour water into the radiator with a water hose connected to an outdoor faucet. Only allow it to run for a few moments. Do not let the bucket overflow.
Empty the bucket into a plastic container. Antifreeze is deadly and shouldn't be stored in an open container where children or animals can reach it.
Continue to run water through the radiator until it pours out clean. Turn off the hose if the bucket gets half full, because the water still in the radiator will fill the rest of the bucket. It may take a few full buckets to completely flush the radiator of sediment, so empty the bucket when it fills and continue the process.
Replace the drain valve with a socket wrench. Fill the radiator with a mixture of equal parts antifreeze and distilled water. Do not use tap water because the sediment and minerals in the tap water can build up in the radiator.
Start the 4Runner and turn the heat controls on high heat. Let the engine run for two minutes, then continue to fill the radiator. As the engine runs, the coolant will be pushed through the lines, making room for more coolant in the radiator. When the radiator is full, put the radiator cap back on and push down while twisting to secure it.
