My car is a 98 S70 non turbo 148K miles- Last summer the AC was not cool so I add 1 can of freon to the low pressure side- It worked great and pressure was steady at about 31 pounds. Today turned on AC, warm air and the clucth cycles continously about every 10 seconds. I go to add another can and my gauge goes from about 15 pounds to 50 pounds each time the clucth engages / disengages- Dont want to blow anything out- Ideas?

 

you probably have a leak somewhere, and leaked it out over the winter the clutch is disengaging because the pressure on the low side (the side you have the guage attached to) is dropping to low. when first started with my AC I had to put about a half can in to get to the point you are at right now, kept filling and eventually the clutch stayed engaged longer and longer. Finally got the needle to stay in the "green" and it stopped shutting off.

 

Yep, leak. Ended up puting about 3 12oz cans in. There is a pressure switch that controls the compressor clutch on the front passenger side that I removed and used a paper clip to jump, for the first can, this keeps the compressor engaged to while filling. Only ended up with about 25 pounds but very cold air coming out

 

you don't want to short the pressure switch when you're leaking gas coz that is there to prevent compressor damage when you are low on gas thus low on lubricant, your compressor will seize and or throw all sorts of metal scrapings into your whole system and you will end up with a big clean up, if you're not lucky, then you're up for replacing everything in your system

if u are leaking so much freon you probably have no more lubricant left in your system anyway, and you will have other contaminants like moisture and air which is no good, probably best to fix it up probably asap or expect a big repair bill down the track

 

Good point, the freon did have oil in it. Have done minimal work on AC before. Hate to pay when I can wrench myself. So should I take in and have vacuumed etc?

 

yeah, best to check and fix all the leaks, flush the system, replace the orifice tube and receiver dryer and valves, o-rings, vacuum the system to remove all moisture, then regas with the correct amount of R134a and oil as listed under your bonnet.. then it should last you for another 5+ years if nothing else breaks or leaks