To determine the antifreeze capacity of a vehicle, check the owner's manual. Alternatively, drain the radiator and overflow reservoir, and fill a known quantity of water in the radiator until its level touches the piping of the expansion tank. The amount of water required indicates the vehicle's antifreeze capacity.
Most owner's and instruction manuals provide the antifreeze capacity of the vehicle along with other specifications. If the manual does not contain this information, check the capacity yourself.
Drain the radiator of the vehicle by keeping a catch pan beneath it. Remove the drain plug of the radiator using a socket and ratchet. Similarly, remove all the antifreeze from the overflow reservoir, and dispose of the fluid appropriately.
Open the radiator cap. Ensure that the cap is cool before removing it to avoid injuries due to hot antifreeze. Fill several 1-quart cans with water, and pour the cans one at a time into the radiator. Note how many cans are required to fill the radiator to the tank piping level. Generally, the radiator capacity of vehicles ranges from 11 to 28 quarts.
When the water reaches the required level, calculate the total quantity of water used. Empty the radiator, and pour an equal quantity of antifreeze into it. Record the antifreeze capacity for future use.