I recharged my A/C a few weeks ago with standard R134A and everything seemed great for a while. It blew cold (enough) for a while but then started blowing cold intermittently. I thought it may have been a slow leak and be slightly low on pressure. I then used a bit of A/C Pro after reading great reviews and it having a mild "leak sealant" that I thought may help. I only added a small amount and maxed out the pressure in the green safe area then accidentally went slightly into the yellow (but nowhere near red)

The A/C seemed to work great again. It was colder than ever but then I realized it was still intermittent. It would often work when first starting the car then if I stopped for gas and restarted the car the compressor would not start/stay running. Once it stops working it seems the only way to get the compressor back on is to restart the car which works infrequently. If I attempt to cycle on and off the A/C switch, fan, etc. it nevercomes back on.

I replaced the A/C relay in the engine bay by the firewall on the passengers side (front passenger side relay in a set of 4 by firewall). It did not have any affect.

The compressor/AC worked yesterday for a 2 hour drive but as soon as I got gas and restarted the car it would not come back on. I parked shortly after and restarted the car ~4 times but couldn't get it to come on. I heard it attempting to but it wouldn't stay running.

I just did another 2 hour drive with no A/C. I parked and restarted the car and the compressor came on and stayed on for ~5-10 minutes then turned off and the air got warm. I'm sitting in my car no cold air. The AC button is on (green) and doesn't have any effect if toggled on and off. The only way I can seem to get the AC to work is to restart the car in which case the compressor at least attempts to engage and then there is a low chance that it stays on for an undetermined period of time before shutting off and blowing warm air again.

Thoughts?

 

You're adding Freon (actually not "Freon" anymore) and crappy additives and nowhere have you tracked down the leak and fixed it. Standard procedure is to refill the refrigerant and add a UV dye with it. Then you wait a couple weeks or so. As the refrigerant escapes through the leak and vents off into the atmosphere the dye is left behind. Follow the refrigerant lines with a UV flashlight in a dark garage and the light will pick up the fluorescence the dye produces, pinpointing the leak(s). Fix leak then top up or replace refrigerant.

 

I should have clarified better. There is no leak or if there is it is extraordinarily small. I thought the reason the compressor was not coming on consistently was due to low pressure but when I went to add the AC Pro it was still at the same level in the green as several weeks before. I just "maxed it out" in the green (slightly over). I can get an exact pressure number later but the pressure is definitely good if not slightly high. When it works it works fantastic but the compressor just doesn't always stay running. Especially if the car is turned off and turned back on. It worked for two hours yesterday but as soon as I got gas and started the car again the compressor wouldn't stay running regardless of cycling/restarts.