R134a Refill Question(s)

[packman]

I just refilled the a/c system in my '05 MGM over the weekend. I discovered last year whilst installing the headers that my accumulator kicked the bucket. As such, I refilled the system according to the fan shroud tag (38oz). However, I put 4 cans (48oz) and was barely in the green zone of the gauge (with the car running and a/c on full blast). I didn't want to put anymore in there, as it was a bit over the stated 38oz capacity. Should I have put more in there? Or should I leave it alone and be happy that I have a/c again?

[gadget73]

refill is done by weight on these, but if you did not vacuum the system down the pressures are going to be screwy. Hopefully you did, moisture in an AC system will screw it up pretty badly.

clogged orifice tubes also make for low low side pressure, which is why you really want a proper set of manifold gauges to do this.

[tbear853]

Our '01 Mercury GM has 94,9xx miles, we've had it since new, it has always had good cold air, and it has never needed R134a added to the factory charge.

Monday on the way to town to get it "inspected", outside was well into 80s and the MGM's MAX AC was only blowing 50* air, it seemed weak to me.

Tuesday early AM, it was 70+, maybe even 75 degrees out. I got my gauges out. Interior opened up, car idling, MAX air, high fan, AC was "short cycling" a little, gauges said 25 psi on low side. So I hooked a can up, slowly letting R134a gas (can right side up) go in, brought it up to steady 35 psi and stable. Compressor had stopped short cycling & was staying engaged longer. Air out the vents was down to 39* now and it felt very "crisp".

Weight of the can with hose tap still on it had dropped by about 8 ounces, was not much left in that one 12 oz. can.