AC works only for the first 30 minutes

Hello,

If it starts out only blowing Cool Air, Not Cold and turns warm to hot I would think low charge. Would have it checked, recharged if needed and have a dye added to check for leaks.

OK, how long has it been blowing cool air? It is a good possibility that it is just low on charge I myself will always when I do recharge put in a dye to be able to test for leaks if happens again in short period of time like a month or so.

Can you hear the A/C Compressor kicking in and out every 5 or so seconds, if so good indication of low charge. Another possibility is a Clogged Orifice Tube which is in the line somewhere.

Here is what I do -

1) Charge a/c to include Lead Detection Dye - If starts blowing Cold Air and Gauges show full on both High & Low side done.

2) If Charge doesn't work - Check for leaks using UV Light - Make Sure to Check the Condenser in front of the Radiator.

3) If No Leaks Found - will find Orifice Tube and Replace

After that if still doing same I would check Blend Doors, if they are working properly then most likely the A/C Compressor is bad.