Cool air is blowing in but if it's 95 outside, the car doesn't get cooler than 85 inside. I decided to add some R134a. Ran the AC for 3 minutes. Gauge said pressure 40. I started to add a can (AC running). Then it started making a clicking noise every few seconds. I turned off the flow from the can. The clicking continued. The pressure was about 42, then a click, then pressure up to 62, then another click, pressure down to 42 , etc. The clicking never stops now, but it never clicked before I added R134a. The air coming into the car still feels cool, but not cold. Should I try adding more R134a?

In other words, is it possible that if pressure is really low there is no clicking, but raising pressure a bit makes clicking start, and raising it even more would make the clicking stop?

 

If you keep going down this path you will likely blow seals. The only way to do this right is to recover the system, pull a vacuum and install the proper amount of refrigerant.

With high temperatures, it will take a while to remove the heat load from the vehicle. Before the fan drops to lower speeds, it might take up to 20 minutes of driving.

 

Before I added any Freon I gave it plenty of time to cool down inside the car, but it never did. I tried adding the rest of the can this afternoon and found it was empty. AC still clicking, which it did not do before I added Freon. I'm taking the car to a shop on Mon. and won't run the AC before that. I haven't driven the car while the AC was clicking. I suspect a leak resulting in low pressure, but I can't explain the clicking starting only after I added a can of Freon. I'll report what my shop says.

 

I suspect that the "clicking" is the compressor going in and out also called "cycling". That's normal, if that is what is going on. However, if you are running the fan on high and the compressor is cycling I would suspect a low refrigerant charge. Those cans only hold about 12 oz and if the air is not cold typically one can will do it. However, the only way to do this right is to recover and recharge.

 

My car is fixed, at least temporarily. The shop had to evacuate and recharge. It still wasn't cooling well. Then they turned the temp control ***** to full heat and back to full cool. That fixed the problem for now. Something was wrong with the blend doors, but we are leaving well enough alone for now.

 

They should have checked for codes in the HVAC module.