Recharged my A/C on 1999 F150 Super Cab with 5.4 engine. At startup and low speeds A/C works fine. At higher speeds and after engine warms up, no cooling. Has full charge and no leaks that I can find. Any ideas?

 

Check for evaporator icing.

After how long of a period of operation does the failure occur?

Steve

 

I THINK SYSTEM IS NOT CHARGED PROPERLY. ON AUTOMOTIVE A/C I PREFER TO WEIGH REFRIGERANT IN. TAG UNDER HOOD OR ON RECIEVER TELL YOU EXACTLY HOW MUCH. BUT I HAVE AN ELECTRONIC SCALE TO USE. CHARGING BY PRESSURE IS GUESSWORK. DID YOU RUN ENGINE AT 1,500 RPM WHILE CHARGING ? IF NOT TRY THAT AND CHECK YOUR GAUGES, I THINK YOU WILL FIND YOU ARE LOW ON REFRIGERANT.

 

Also make sure you have a high volume fan blowing into the condensor coil up front