I have a 1997 ford aerostar and my mechanic just called me and said that the pop off valve needs to be replaced, but it is attached to the line so the hole line has to be replaced to. I want to try to find the pop off valve to see if I can get it b/c he can't find the replacement part, what I need to know is what it looks like. or where it is on an aerostar, because I have 5 more sitting in the driveway and I can look for it.
1. the pop off valve is normally located in the compressor so if it over pressures it will relieve some of the pressure. it's not in a line. #2. if it's a 1997 it doesn't have R12. it has R134. the only valve in the line is the port to check pressures and vacuum and recharge it. it could have one of those valves leaking and most can be taken apart and a new schrader valve installed. hope this helps.
Well, for AC, you can have the old school R12, that looks like a tire valve. New school is high and low side R134. These 134 ports are usually located on the fitting that is crimped to the hose. A new hose would be the only option. If you have the old R12 style, they sell an adapter for $5 that will convert it to a 134 high side.