[Matt L]

If your compressor is not turning, r134a will not go into the system.

The tool to measure and add refrigerant is called a charging cylinder. If you have one with a heater, you can easily install the refrigerant to the system without starting the compressor.

I just did it last week, to replace the refrigerant in my car. I didn't start the engine until all of the required refrigerant had left the charging cylinder. Starting the engine at the end is necessary to let the compressor remove any liquid refrigerant remaining in the high-side service hose.

 

[Matt L]

In addition, if your old compressor had internal damage, you replace the condenser and flush the rest of the system.

 

[Matt L]

How did they determine that you had refrigerant in the system? There is only one accurate method, and that is to extract and weigh the refrigerant, and shops don't do this for free.

I can see a shop putting gauges on a car and saying, "You need a compressor," for free. Of course, they will expect a healthy check for the compressor in the near future.