a/c problem, a/c does not blow cold air

Hi, I have a 2001 GMC Yukon XL. I'm having problem with the a/c. When I turn it on it will work fine at first for the first 30-45 minutes of use, the a/c blows cold air. But after that the a/c does not blow cold air anymore. It'll just blow warm air. I already checked the compressor, new ac relay, R134 pressure is ok,.. any idea anyone? what could cause the a/c to stop producing cold air? thanks

you need more 134a. Try adding more 134a. It should accept more refrigerant without the pressure rising. Stay within the limits of the gauge though.



Hi, I have a 2001 GMC Yukon XL. I'm having problem with the a/c. When I turn it on it will work fine at first for the first 30-45 minutes of use, the a/c blows cold air. But after that the a/c does not blow cold air anymore. It'll just blow warm air. I already checked the compressor, new ac relay, R134 pressure is ok,.. any idea anyone? what could cause the a/c to stop producing cold air? thanks