After sitting this dinner my AC quit working. I added a regular can of coolant and now it is cooling, should i add another one?

 

No way to know unless you read the pressures. Two ways to determine how much to put in.

Attach a gauge to the system and add until the low side runs about 40-45 psi when the compressor is running.

Or the more accurate way, suck the system down to 30 inches of vacuum and refill with the exact amount of R134-A the system is designed for.

 

The clutch cycling switch on the accumulator cycles the compressor on and off to maintain low side pressure between 22psi and 42psi **. This keeps the average evaporator temperature at 32 degrees. Condensation on the evaporator fins doesn't have a chance to freeze, (ice up).


The only way to know how much refrigerant is in the system, is to drain it, evacuate it to 29.4" for a minimum of one hour, and recharge it with the proper amount of R134a refrigerant.


If you add the specified amount of refrigerant without evacuating the system first, the system will be overcharged and it will not cool properly. If you add refrigerant to bring low side up to 40psi to 45psi, the system will not cool properly, and it will be dangerously overcharged, don't do it.


**R134a refrigerant is approximately the same temperature, as the pressure it is under, (40psi = 40 degrees).

 

Good info. I will need to recharge my system when I put the compressor back on. I think I will have to ad a bottle of oil to it though since I took the compressor completely out. Waiting till I get the new gatorback belt in the mail though before I do this.

 

The compressor does not have a "crankcase". Oil is in suspension throughout the system. Knowing exactly how much oil is in the system is nearly impossible. If you over or under charge with oil, it can "slug", (destroy) the compressor. Best to empty the compressor and measure how much oil comes out. There is a formula for calculating how much oil to add to the new compressor.