Put the can of refrigerant in a pan of hot water from your faucet, helps it flow in. The compressor will cycle until it is almost full 2 cans plus a bit more if empty. I recently discovered the valve you put the refrigerant in with was leaky on my car. Ford dealer should have one, and you will need an a/c valve tool. There were bubbles in the valve oil residue after charging. After a new valve and more r134, so far, it's cooling well.
