The Stovebolt Site Forums The Shop Area The HiPo Shop A/C question

Like Buck says, my Vintage Air system was overcharged during a 500 mile road trip at 100 degree temps. I had used one of those "can with a gauge" R134 kits that you buy at FLAPS or Walmart to do a last minute A/C tune up before leaving on the trip early one (cooler) morning. Once the day got hot the overpressure switch would kick in, disengaging the A/C clutch for a few seconds. The pressure would drop, the switch would reset, the clutch would engage and the whole process would start over. At its worse, the whole cycle was happening about once every 3-5 seconds. And no cold air into the cab.

Don't tell the EPA, but my "on the road" solution was to set the idle high by pulling the hand throttle knob while the A/C was running. Then I used a small screwdriver to depress the Schrader valve on the high side of the compressor for a half second or so. That let out a little of theR134 and the "cycle time" of the overpressure dropped 2 seconds or so. Two more quick discharges of R134 and the system quit going into overpressure. I drove the rest of the way home in air conditioned comfort.

Moral of the story is "don't use one of those one can, a hose and maybe a gauge" recharge kits".