The summer may be over, but that doesn't mean you should leave your air conditioner languishing until it starts to get hot again. Air conditioner compressor systems can wear out over time, and they may need to be replaced, which also requires a change of the coolant and the oil used in these systems. Fortunately, most owners should be able to handle this task.
First, you'll need to completely flush your compressor of any coolant that is left over. Most garage and oil change facilities will do this for free, because they get compensated for collecting the coolant and freon, which must be handled in a specific fashion.
Then, you can remove the compressor on your own. Find the coolant line bolts and rotate them counterclockwise. You'll probably hear a slight hissing sound as you do this, but that's nothing to worry about. You should notice an A/C pulley system with a tension arm. Press on the arm and slide the belt off of the wheel, then release the arm to get more slack and unwrap the system completely. You can then remove the compressor from the mount arms and take it out of the engine compartment.
Installing the replacement compressor is simple - just repeat the above steps in reverse order. Now all that's left is replacing the coolant and oil. Fortunately, there's a pretty easy way to do this. An A/C recharge kit comes with everything you need to replace both of these critical components for the air conditioning system.
Attach the can of coolant onto the valve trigger that comes with the charging kit and twist it clockwise until it locks into place. Then, locate the low pressure line on your A/C system, which should be running between the compressor and evaporator. The nozzle is designed to fit over the nipple located on the end of this line.
Once the nozzle is attached, turn your car on and put the A/C on full blast. Then return to the valve trigger and pull it to dispense the coolant into the system. You don't need to move the can at all - it should empty the coolant into the system in about five minutes. Then, simply do the exact same thing with the can of oil.
With that done, your A/C system should be as good as new - and you won't get a nasty surprise next summer.