Repairs to a 2001 Honda Civic's air conditioning should be left to certified, professional mechanics. Recharging freon levels is more of a routine act of maintenance, not an actual repair job. It is a relatively simple task, and repair kits are widely available at most automotive retailers. A 2001 Honda Civic takes R134a freon, which is also widely used on cars manufactured after 1984. Do not purchase R12, as it is not only bad for the environment, but it will not work in a Civic's air conditioning system.
Connect the recharging kit's hose to the kit's R134 can. Exercise care while doing this. The kit's valve is also meant to open the can and release the freon. So do not turn the valve all the way down.
Open the bonnet of the car. Locate the 2001 Honda Civic's low side port. The air conditioning system uses aluminium tubing, and the low side port is the outlet located more towards the front of the engine. Leave the high side port alone. The kit's hose is not prefigured to fit it.
Attach the hose to the Civic's low side port and find a place to temporarily put the kit down. This should be away from any movable parts within the engine, like a belt or a fan.
Sit in the Civic's driver seat and crank the engine. Let the Civic's engine idle until it is warmed to it's usual running temperature. Insert a thermometer into one of the air conditioning vents and switch the air conditioning system on. Set the system to maximum levels on air temperature and blowing capacity. Monitor the thermometer.
Remove the thermometer once the air conditioning system gets as cold as it can. Leave the Civic's doors open once you return to the recharging kit and the Civic's engine. This will keep the system from accidentally cycling off.
Turn the valve atop the recharging kit all the way down until you hear a gassy, rushing noise. This will be the freon charging the system.
Turn the valve and close off the connection. This will allow you use the recharging kit's gauge. You will need to let at least one minute elapse between charges into the Civic's air conditioning. This will allow the system to stabilise.
Look at the aluminium tubing while you charge the system. The recharging process will eventually turn all the tubing uniformly cold. Place your thermometer into an air conditioning duct and watch the temperature withing the system. A Honda Civic's air conditioning will settle to 40 degress once the system is charged.
Remove the kit from the low side port either when the recharging is complete or the can becomes empty. If you need to switch cans while recharging, avoid overfilling the system at all cost. Overfilling will damage the Civic's air conditioning.
Turn off all the running components within the Civic. Close the bonnet. Store any left over R134a in an upright position, in a closet or storage space where there are no radical or sharp shifts in temperature. Leave the kit attached to the can of R134a freon.
If the can becomes extremely cold while recharging the Civic, try wrapping the can in a towel.
Even if this is routine vehicle maintenance, wear gloves and protective eye goggles. R134a is compressed gas, so err on the side of safety.