I have been thinking for some time now that my air conditioning could be colder and today it hit 95 degrees and the air conditioning in the truck was very slow to cool. I decided to buy a can of the refrigerant stuff from autozone to see if this would help. I measured the pressure before i began and it read 35 psi. Following the instructions I started filling the system, periodically releasing the trigger to check the gauge. The problem is the gauge never moved from 35. When I pulled the trigger the gauge would return to 0 but even after I drained the entire bottle the gauge had only moved slightly (less than 1 psi). After I turned the engine off I could hear a hiss (don't know if this is normal or not). The instructions on the bottle said that for the temperature outside the pressure in the system should be about 50-55 psi. My question is did I do something wrong or do I have a leak like I suspect? It doesnt seem right to me that the pressure would not increase at all. Any ideas?

Thanks,
Peter

 

Take it to a professional to be properly checked out. The ONLY way to properly charge the system is evacuate it with a vacuum pump, leak check it, and recharge it with a weighed amount of refrigerant.