I did a compressor job on my brothers 85 Chevrolet K20. All new components. R12
I had two sets of specs on the charge. One said 44 oz, the other 48 oz. To make matters worse, the stock condenser is no longer available. The aftermarket replace looks OK, but is different. Not sure how that will affect the capacity.
We put in about 3.5 12 oz cans. It cooled well on city streets , but was warmer on the highway.Low pressure was about 38 , high 180 about 90 degrees out. I guessed a slight overcharge, and took a little out Temps improved, but the compressor low cutout switch wasn't working.. It got as low as 36 at the vent, (at night) and no cutout. Put a new switch on and no change.. Grasping at straws, my brother started removing what looked like factory tape around the wires going to the switch. He found the problem. someone had stripped about 1.5" of insulation from both wires and twisted them together... Effectively bypassing the switch.
We redid the wiring, and checked the pressures About 85 degrees out, Low 32 @ idle, dropping to 29 @ 1500 rpm. High about 170.
We took a road test, and it still cools better on city streets than the highway.. We got down to 48 on the highway. 46 on city streets. The temp holds very well , and sometimes even drops a little at a red light....
The fan clutch is a new heavy duty one.
The high pressure line from the compressor to the condenser is hot. The line from the condenser to the orfice tube is close to ambiant. The evaporator inlet right after the orfice tube is cold, the evaporator oulet tube is colder. sweating a LOT, as is the accumulator, and the line going from it to the Compressor suction port.
I cannot see how it is possible, but it seems to still be a little overcharged???
Should the line be sweating at the point where it enters the compressor?