Auto Air Conditioning & Heater Repair: A/C Blows Cold For Approx. 10 minutes, then Stops, nissan altima, coolant temp

Question
My 1995 Nissan Altima's A/C will blow cold for approx. 10 minutes, then the compressor shuts off and no more cold air.  When the A/C does work it blows very cold.  The A/C system has a triple-pressure switch mounted on the receiver-drier, a thermal protector switch located in the compressor housing, and a thermal control amplifier mounted on the evaporator housing, all of which will stop compressor clutch operation.  I added a can of refrigerant/oil/stopleak about 3 weeks ago and it did not fix the problem.  About 1 week ago I purchased manifold gauges and checked the system operation pressures, which were all within range on a 80 degree day and engine speed at 1500 RPM.  I did notice that the low pressure line from evaporator to compressor would frost up a little when compressor clutch was engaged, then as soon as compressor switched off, then the line would heat up.  What do you most likely think is the problem?  The thermal control amplifier can be replaced without evacuating the system, but I am not sure about the triple-pressure switch or the thermal protector switch on the compressor.  The only other repairs I have made to the vehicle this year is new radiator, hoses, waterpump, thermostat, coolant temp. sensor and  sending unit.  The only thing that I noticed after the repairs that didn't happen before is my fans will run for about 30-60sec after shutting of the car.

Answer
hello john,any Form  of frosting on lines are usually caused by restriction at the expansion valve. Normal reading for a/c at 1200rpm low side 25 to 35psi and high side 190 to 210psi.you may have a thermostic switch in the evaporator housing that is design to control evaporator freeze-up. that could be the problem also.

Good luck,davidt