Auto Air Conditioning & Heater Repair: 1997 Chevy Suburban A/C System, chevy suburban, engine coolant

Question
Last year I had the ac system changed in my suburban because it quit cooling.  I took it to a local shop that deals with ac systems (not exclusively).  They so say changed out the system, compresser dryer, etc.  It wasn't cooling like it did before the change so I took it back, and they told me that it wasn't gonna get below 60 degrees.  It wouldn't even get below 70.  We have been fighting to have the problem fixed since.  The heater works great but it still won't cool.  They have replaced the compresser 2 more times and still is not cooling.  It will not get below 70 degrees on max ac high fan.  THe other day I was having trouble with a severe squeak when my truck was idling and got worse when I would put on the gas (brand new belt).  It would quit if I put belt dressing on but not for long.  Then my husband noticed that the freon and leak stop that the "mechanics" put in my ac was all through the engine compartment.  So they replaced the compresser again (so say).  The engine coolant keeps running out now and the back fan motor is very loud.  Do you think you may be able to diagnose my problem so I can get this thing fixed once and for all.

Thank you

Answer
Hi make sure they are using New compressor not rebuild also make sure the fan on the front of the engine is drawing plenty of air through the condenser and radiator- poor air flow will cause high pressure and the freon will realease from the  high pressure valve on the rear of the compressor   and have the recurlate door checked it may be in the outside air mode all the time.  sounds like the rear fan may be going bad or may have debree in the wheel or housing     the rear expansion valve may need to be changed if the compressor failed it may have seent particulates into the valve restricting or blocking the freon flow  the front orfice tube needs to be checked as well for same type of contaminates