97 blazer 4.3 auto

last summer ac worked fine. every year or so i have to add some feron, less than a can. this year no work. using my can guage it showed over charge. my friend who is an old school mechanic put his good set on it and said it was low charge, he added about 20 ozs. low pressure is 50 and hi pressure is 150 psi. air temp was 35 F using IR temp probe. an hour later I took it for a ride and no a/c ir probe was ambient temp. put gauges on and and pressure were still 50 /150. he thought there may be an internal blockage (orfice tube). before we added freon compressor was cycling, after adding it stayed on. it is still on and not cycling now. any thoughts????

thanks

bernie

 

Could be a bad pressure switch or orrifice tube.

 

thanks, Any idea what color orfice tube is and where it is located on the 97?

again thanks

bernie

 

Its inside of the inlet tube (smaller diameter tube) going into the evaporator. Keep in mind if you open the system to replace it you need to get it evacuated first! And you should also replace the accumulator while you are at it. Then refill your system.