2007 Mazda 3s – Air Conditioning Recharging Issue

Hi guys, first time post long video watcher on youtube. Thanks for sharing your knowledge Eric!

Ok, I have a 2007 Mazda 3s (114k miles). The a/c has been working fine and when the summer goes around I have been topping off the r-134a. This year I wanted to try to see if I had any leaks. I had the car’s r-134a evacuated. I then vacuumed out the system like I have in numerous other vehicles. 45 minutes later I turned off the high and low side valves and then the pump. I then let the system sit for 30 minutes, no leaks.

So looking at the Mazda 3 service manual, it says that “charging should always start on the high side”. Something I have never experienced in all my other vehicles. Manual says to charge till I see 14PSI on the low side gauge. The manual warns about running the engine when charging from the high side (Cans can explode). After reading online, I opened the high side with the engine off. Being that the system was under vacuum, it pulled in some the freon. Mind you I have the low side valve closed. I kept my eye on it to see if it would bump upto the 14PSI. It did not.

Once the high side stopped sucking in freon. I closed the high side valve. I then started the car, turned the A/C to On and flipped it to position 4 (high). I then open up the low side valve and it pulled in a bit of freon. I also checked the clutch and it was engaged as soon as I turned the A/C to ON.

However here is the problem. Last night I did this process, based on the weight of the cans and how much the system needs, I did not fully fill the system. The A/C was however working, not fully but it was cooling the air when I drove home. So I called it a night, shut off the A/C, closed the low and high valves and the freon can then went home.

Today, knowing that I had not put 17oz of freon in the system, I decided to try and add the remaining freon. I hooked up the gauges, hooked up the freon can, burped the lines, and turned the car on and AC on. The car wouldn’t take any freon on the low side after 30 minutes. So not understanding what was happening at this point, I decided to re vacuum the system all over again.

This time around the high side didn’t pull in as much freon as last night. I believe I pulled around 200 psi last night and today only about 100 PSI. Again with the car off. I then closed the high and opened the low and it also pulled some freon around 100 PSI as well. I then started the car, AC on, and heard a really funky sound coming from the compressor for about 10 seconds before it stopped. I then went ahead and opened the low side valve and the car again would not pull any freon. Clutch is engaged.

So between today and yesterday I could not replicate getting my AC to work, not to mention that I heard a funky sound from the compressor today.

Thoughts?

Specs:
2007, Mazda 3s, L4, 2.3L, USA