I have a 2013 Tacoma V6 with 138,000 miles on it. Had a few issues but I worked through all but 1. A/C line going to the front of the vehicle has a green residue on it. A/C still works but I know it's only a matter of time. Either a hose or an O ring. Does the green residue tell me what kind of oil is in it? Does the fact that it is green say that someone has already put something other than what it had originally? When I vacuum it down does the oil come out also? Thanks for any for any info!!!