I was sitting in a parking lot with the engine at idle on a hot day with the AC running. Suddenly there was a loud "pop" and lots of what looked like smoke came from under the hood. I shut down the truck, opened the hood and the "smoke" was coming from the firewall where the AC lines penatrated it. The AC now does not run cool. I suspect the "smoke" was accually freon leaking from the system.

My questions are, What component is the one that failed?, and does this moel F-150 use an orifice tube or an expantion valve?

Friends have suggested both of this components my be my problem.

 

The 2002 F-150 uses an orifice tube. You'll need to pull the old one to determine if your particular F-150 is using a RED or BLUE orifice. Id the orifice is covered in grey to black crud, then your compressor may be shot (BLACK DEATH). That would be another ball game.

 

In my original post I said that the vehicle was a 2002, but actually it's a 1992.

 

Orifice color is the same for the 1992 model. Either red or blue. Being a 1992, it's using R-12. I personally would keep it as R-12 even though the R-12 will cost more. R-12 to R-134 conversions just don't run up to par . Your system takes 44 oz. of R-12 and 10 oz. of oil. I would get replacement parts here http://www.techchoiceparts.com/listitems.aspx as they are cheaper and I use this site for A/C parts. Get some Polymax2 oil from here http://www.autoacsystems.com/_store/..._itemsoil.html. It's a non hygroscopic oil and will not absorb moisture and also will not mix with the oil.