Coolant, or antifreeze, protects a car's motor from rust and corrosion by providing a cooling system that prevents overheating. Honda recommends that the coolant in a Civic be changed every 120,000 miles (192,000km) or 10 years, and every 60,000 miles (96,000km) or 5 years thereafter. Doing so will increase your vehicle's longevity.
Start the car and slide the heater temperature control switch to maximum heat. Allow it to run for one minute, then turn the car off.
Use the jack to lift the car and safely secure a jack stand on either side of the vehicle. Raise it high enough that you can fit comfortably beneath it with clear visibility.
Pop the bonnet and make sure that the radiator and engine block are cool to the touch. Only begin work if you haven't recently driven the car. Otherwise the cooling system will be under pressure, putting you at risk of being scalded.
Locate the battery for removal. In most Honda Civics, it is found in the upper left side of the engine compartment. The battery is the black box with two cables attached to the top of it.
Always disconnect the negative terminal on the battery first to prevent short-circuiting the positive terminal to a grounded part of the vehicle. The negative will be labelled with a minus sign. Loosen the metal clamp with your wrench and slide it off the terminal. Now disconnect the positive terminal using the same method.
Unfasten the battery holder and carefully lift the battery from the car. Batteries can be fairly heavy, so take your time.
Locate the radiator near the front of the engine compartment and slowly release the radiator cap on top.
Fashion the oil pan directly below the radiator to catch the coolant. Put your protective eyewear on and loosen the drain plug located at the bottom of the radiator to flush the coolant.