Volvo: Self help - recharge freon, saftey glasses, compressor cycles

Question
Hi:  I'm very strapped for cash and am preparing my 89 Volvo 740 for my son for his first car.  I see my local department store sells freon.  What do I need for equipment and what steps do I take  to to recharge the AC?  Compressor cycles on and off every 4-5 seconds and blows slightly cold.  Thank you.  

Answer
Corey,
Sounds like it is low on freon. It should be using R12, but you really are not sure! It should be tested to make sure. However if your a gambling man just charge it with R12. You need a hose and can tapper and the freon. Charge it through the valve on the drier with the compressor running. Since you are topping up the system do not use more than 28  ounces of freon. There is no way that you using cans of freon will be able to gauge when the sysytem is full. So I base my threoy on the fact that the compressor works and some cool air comes out. The compressor will work with about 11 to 16 ounces of freon. Any more than the 28 ounces will over fill the system. Wear saftey glasses while you work, being careful of the freon.