My car was not blowing good cold air. Friend of mine that said they do what they were doing but a can of freon. The whole can. Did not know that the low pressure gauge would not budge past 30 to 35 since it has a regulator. I also got curious and check the codes on my air conditioners control system and it came up of course code 24. But my car changes from all the vent positions with the air blowing out properly. I know I've got some loss because I bought the car was 67,000 MI it's a 1998. First time I ran the heat and cooling system all kinds of black grit blew out everywhere. I had realized that was all the foam that dried out in the system. So there's got to be very little foam left on anywhere it was previously located. Could that simply give me a code 24? And the heating and cooling problem is my friend putting way too much freon in it?