Most vehicle engines are water-cooled, meaning that a water-based coolant is circulated through the engine passages by the water pump. The coolant passes through the radiator, and than back through the engine. However, the coolant must be removed from the engine and radiator when repairs to the cooling system are needed. When the system is then refilled, there may be small nooks and crannies that trap air pockets. This air must be bled from the cooling system before it will function properly.
Drive the vehicle onto a set of car ramps, which raises the filler neck of the radiator or coolant recovery tank higher, possibly helping to eliminate some of the air pockets in the cooling system. Place wheel chocks under the rear wheels. Open the hood and remove the radiator cap or coolant recovery tank cap, if your vehicle is so equipped.
Check the owner's manual for your vehicle to find the coolant capacity of the cooling system. Have ready a mixture of 50 percent coolant and 50 percent distilled water in this quantity. Place a funnel in the radiator or coolant tank opening and begin pouring in coolant until it reaches the full mark. Skip this step if your cooling system has already been filled.
Start the engine and let it warm up to operating temperature, usually about 15 minutes.
Observe the level of coolant. Add coolant as needed to bring the level back up to the full mark. Continue to let the engine run for a few more minutes. Repeat this procedure as many times as necessary until the coolant level no longer drops.
Replace the radiator or coolant tank cap and close the hood. Remove the chocks and back carefully off of the ramps. Watch the coolant level closely over the next few days and add coolant as needed to bring it to the full level.
