Lev , Tony is only expressing what the SOP would be for any AC system where the cooling is not functioning per it's design. In all of the classes I have taken on the subject this was stressed in order to prevent loss of gasses and contamination of the system. Topping up is OK to do especially with the freons that have leak seal capability but contamination is the system killer. As I mentioned the 1st thing I was trained to do was install and read the gauges. Once you understand the readings then you can go from there. The non climate control systems are easy to diagnose and repair. So if I were to look at a temp vs pressure chart and see that there needs to be an add to get it to spec and see where you are . With all of my vehicles except the Volvo I have never had a leak but usually sold them before hitting 75K miles . My 89 blew a condenser at 200K and then blew a hose 50K later which took out the compressor. So at 300K I have replaced everything except the evap.

 

Since we are at this topic, does anybody know if you can tell if a compressor is OK short of having it installed and plugged in, and belted and all?

 

I suppose you could rig up a test stand, where you spin it with an electric motor, and hook it up to a fluid circuit with a restrictor valve and pressure gauges...

 

This is a similar type system but you can rig one up.