Hi April Darmody. Welcome to the forum. No need to retrofit anything as the newer R-134 has been in use since 1994. First you have to determine if the system is low on charge. Overcharging can destroy the compressor if liquid refrigerant makes it into it.
If the compressor is not running, one way to test it is to find the low pressure cutout switch, unplug it, and use a paper clip or piece of wire to jumper the two terminals in the connector while the engine is running. If it starts to run and it cools a little inside the car, it is likely just low on charge. That would be typical after nine years.
If the compressor is already running, feel along the hose that runs from near the radiator to the firewall. It will be cool but you're looking for a spot where it gets real cold. If you find such a spot, there could be a restriction there, but more likely the system is low on refrigerant and it is vaporizing too soon under the hood instead of inside the car.
The only accurate way to know how much charge is in the system is to have a mechanic drain out and recover the remaining refrigerant and pump in a measured amount. If it appears to be low, you can use a kit to add one can of refrigerant yourself. One can will usually not overcharge the system excessively. It can hold a little extra with no problem. Two cans is too much though. Don't risk damaging the compressor. The hose in the kit will only fit on the low pressure side fitting which is on the hose going from the firewall to the compressor. Always keep the can upright so only vapor boils off and enters the compressor. If it takes more than a few minutes and the can is not empty, place it in a pot of hot water. That will empty it in less than a minute.
If the compressor is cycling on and off normally but you're only getting warm air from the outlets in the car, suspect a problem with the temperature door inside the heater box.
One word of warning; refrigerant will freeze eyeballs and cause frostbite. If you never wear safety glasses, now is the time to start. Many professionals even wear face shields and gloves.
Saturday, June 5th, 2010 AT 2:49 PM