So I've got a 2006 f150 with the 5.4 and it's got a empty AC system that was opened up. I've just been riding around for a while with no AC but now that it is so hot out I need to fix it but not sure about how to go about it. Can I just go get a bottle of r134a and fill it back up or am I gonna need to take it to a shop and have them do it?

 

You have to pull vacuum and get the moisture out. Otherwise, those sweet compounds become acidic with that added moisture. That’s not good.

 

Plus they will want to change dryer. The ice crystals would be floating around in there. And yes it becomes acidic . A full vacuum makes water boil and vaporizes then the vacuum sucks vapor out. They also let it sit to see if it holds vacuum /no leaks .No matter how fast you put it back together it gets wet air in it .