The original systems use a POA valve, not an orifice tube. Same function, but much bigger and bulkier. If you look buy the a/c box in the engine compartment, you will see a rectangle block with 2 lines, and has what looks like a disc on top. There is also a capilary tube that is wrapped around one of the tubes and secured with a sticky rubbery mess...I'm sure there is a name for it..but I have no idea lol