RKB4C

I bought my '95 B4C last year knowing that the A/C system leaks.
The compressor wouldn't turn on (system too low on refrigerant I was told).

I had the A/C tested when I bought the car and know the compressor works. The mechanic charged the system, compressor turned on after he added refrigerant, but then mechanic removed the refrigerant (otherwise he would have had to charge me).

At that time the mechanic recommended I simply add refrigerant each summer since it would cost too much to find/fix the leak and who knows the leak may return w/in a year or so.

Yesterday I bought the kit to add the refrigerant. GM mechanic told me last week to add 1 can first with system OFF. All instructions say to turn A/C ON to MAX.

Which is it? ON or OFF and what's the difference?

Is it harmful to add 1 can first (assume system close to empty if not empty)? Was mechanic telling me OFF because this is a safer way to add refrigerant?

My new kit does have a gauge to tell if I'm overfilling...

Thanks!

RKB4C

OK, I did a search...

It seems the engine OFF mode is the safe way.

How long does it take for ONE can of refrigerant to "fill" the A/C system?

I have the can held high but not willing to risk injury by heating with a hair dryer (as someone suggested in the other post).