R134 recharge question

[Paul G]

The A/C is not blowing as cold as it used to. I bought an R134 recharge kit that has a hose, gauge and fitting to go on the can. First off, the system in my Charger was converted to R134 many years ago, before I bought the car. It has a Sanden compresser with all new hoses.

I put the gauge on the low (cold) side. I was only getting around 20 PSi with the A/C on max and the blower on high. Air temp coming out of the vents was about 45*. I put about 2/3 to maybe 3/4 of a can of R134 in the system. Pressure only went up to 25 PSI, but the air temp out of the vents went down to 35*. I stopped there. Taking the car out for a drive the A/C worked much better. Cruising around with the blower on low the air temp out of the vents was down to 30*. Outside air temp was around 85*.

Should I keep adding gas till the low side pressure comes up closer to 45 PSI?   I ask because I put the gauge on my pickup and the low side pressure was at 45 PSI. I assume 45 PSI is where it should be.

[Chatt69chgr]

I bet that system was supplied by Classic Auto Air.  I would call them before I did anything else.   They did mention when I talked to them about installing one of these systems using stock condenser and evaporator  but Sanden compressor that you use less R134 than you do R12.  Seems like it was .7 times as much.  I would appreciate if you would post what you find out about this.  Thanks and good luck.  I would note that 30 degrees out of the vents on a 85 degree day sounds incredibly good.  I don't think any of my new vehicles does that good.