I top off a few cars every year with tiny leaks. I have the charging scale that you put the 30lbs Freon tank on. And charge with liquid With the system off then start and very slowly add Freon on the low side until the return at the compressor stays cold with the cabin fan on high. It’s easier when really hot outside otherwise it’s a guess unless I Add dye, vacuum it down for an hour and charge back to spec.I'm sure I'm not more experienced than you. I've only been working on AC for 4-5 years but have done lots of self-teaching, reading &research, and YouTube (both on how to do it and how not to do it.) I picked up a Robinair Cooltech 34788 machine at the beginning of the year, for a steal, on Craigslist and it is fantastic. Before the machine, I've been quite successful charging systems with gauges and cans and using a scale. I have NOT been successful trying to charge or "top off" just using gauges. So many say they can do it but I tried early on doing that and killed a system that had no issues to begin with when I got my first set of gauges. I was experimenting a bit with the gauges set when an o-ring blew in the service port coupler on the cheap gauge set I was using and I lost a bunch of refrigerant before getting it shut off. I estimated how much I thought I lost, tried to top it off until the pressures looked good and let it go. A few months later the compressor gave out. I replaced the compressor, condenser, and receiver drier and motored on. The compressor quit a month later and I found a bad expansion valve. Another new compressor, condenser, drier, and expansion valve and the system has been working flawlessly since then.
1. Do NOT try to charge with only gauges. Charge only by weight.
2. If the compressor fails don't try to cheap out and replace only what failed. Go the extra mile and replace the metering devices and flush when necessary.
There are enough people who get lucky and don't kill their compressors that everyone things it can be done. I guess it can but it can get really expensive when it doesn't work out as planned.
Also I agree only use pure R134A. If you fill the system with something else and then take it to a shop? Shop will hook up a Freon detector. If it’s not 99% (don’t know the exact #) the shop will turn you away by law they can’t put it in their recovery machine!! Also Please don’t touch a hybrid A/C system If you own any hybrid car or truck or electric car!! You’ll find out how expensive a complete replacement of every component may cost. And have any of you heard about the newest refrigerant R1234yf? It’s flammable! We haven’t had to use our R12 machine in years now we have to buy a 2nd A/C recovery machine. UghGlad it was easy. I took it from your first post that you had repaired the motor, reinstalled it and it worked after that. Then later on this problem came up. Oh well, glad you're fixed.
Yeah, in the future, don't put anything but pure unadulterated R134a in your system. If it needs oil, put in the proper oil in the proper amount, but nothing but oil and R134a. A small amount of dye is OK, if needed, too. Sealers and other stuff are bad.