Why does ac quit blowing cold air after two hours in a 95 Lexus ES300 Park for 30-45 min and starts to blow cold air?
Next time it stops blowing cold air, leave the engine running,
AC on, and open the hood. Check the AC lines under the hood. If you
see a lot of frost buildup on the AC lines, there's a good chance
you also have frost buildup on the evaporator inside the
air-handler. It's called "icing-up", and it's generally caused by
someone over-charging the refrigerant (over pressure). When you
build up too much ice, the air can't blow past. Correction: My
understanding of the AC theory and many actual occurences over 30
years is that the icing happens when the AC charge is low, not
over-charged. I know this is counter-intuitive, but, if you
research how the evaporator ices up, it has to do with too low a
refrigerant pressure, not too high! So, the solution is generally
to add refrigerant.