That'* true, but I believe it'* mostly because of the law because right after they state "do not mix refrigerants" they state that it is illegal and that it won't offer the maximum performance, likely because R12a has better cooling capability than R134a and if the system is full of R134a obviously there won't be much R12a to improve the cooling capabilities!

I purchased the Red Tek kit and right when I put on the gauge it said it was just about 3 psi, now this was with the car off and obviously the AC hasn't worked in a while. I was a little skeptical since it took just a few seconds to fill to what the gauge said was about 30 psi.

I started the car, AC on highest settings and I filled it up to what I thought was about 35 psi (the gauge read about 70 psi until I relieved the pressure from the canister) and now it always reads about 35 psi from what I can see. I ran it for a few minutes to see if it would change. This is with the canister still hooked up and the valve closed so nothing from the canister comes through.

The compressor started to cycle and the fans came on. Success! Sort of. Well, the system seems to cycle a lot but I'm afraid to add more refrigerant. Maybe every 20 seconds. It'* 17 degrees C out so it'* not hot enough to test the AC, it feels a touch cooler with the AC on but the air without AC on is pretty cold as it is.

I've only used one canister and I feel like it should need a lot more than that but I'm afraid of overfilling the AC as getting the stuff out is harder than it is to get it in.

I'll leave it for a little while to see if the pressure will stabilize so I can get a better reading. I am getting some hissing noise from the area around the alternator so I hope there isn't a leak.

Any thoughts?

You are most likely right, just wanted to add that info just in case it could somehow ruin the system, sounds like with most of the system empty already it could be ok.
I'd keep checking the pressure just in case there is a leak, it is possible that hissing could be one, hopefully not.
Last time mine was empty I had to add two of the bigger cans to mine, I went by the ambient temperature, and added it till it got to the proper PSI listed in reference to the ambient temps.
Keep us updated on how it goes.

I haven't checked the pressure yet but it'* 24 degrees out now and the compressor runs continuously set to 19 degrees. I'm fairly certain the compressor was cycling a lot just to maintain a higher temperature since the exterior and interior temperatures were so close.

The only problem is that the compressor runs a bit roughly - it'* probably normal but the hose that is connected to it vibrates quite a bit and it sounds a bit like there'* a bad bearing somewhere as you can hear it fairly loudly outside the car even with the hood closed, hopefully just the clutch bearing as I'm hoping nothing inside the compressor itself is running that loudly.

It sounds almost like this, and if that'* the case it'* the bearing like the video:


I received an oil level checker with the refill kit so I definitely need to check if I need to add oil or a moisture remover additive before I damage anything. It doesn't blow say "ice cold" but I can safely say it'* certainly "cold".