The EPA
No. NEVER mix refrigerants or use any refrigerant other than what the system is intended to use.
A 1994 and later Ford Explorer will have a factory, refrigerant (R134a) 134a system. In mid 1992 all vehicles produced for delivery in the United States were required under Federal law to have this type of system. Occassionally, but rarely, one will find a late 1992 or early 1993 system that still has refrigerant (R12) 12 fittings. But this is the exception rather than the rule and it is unheard of (virtually) for anything later than 1993 to have anything other than an R134a ayatem. Of course, it is easy to determine which system your Explorer has by checking the service fittings (the place where refrigerant service manifold guages hook up). Although as of last count there were over seventy (that's right!) different refrigerants on the market (all requiring [technically by law] their own exclusively distinct service fittings) there are only two refrigerants that (a) have ever been used by ALL (U.S.) automobile manufacturers and (b) have ever been approved by BOTH the EPA and all (U.S.) automobile manufacturers (concurrently). These are R12 and R134a. If the service fittings on your vehicle are 1/4 inch, male flare fittings, you have an R12 system. If the fittings on your vehicle have no threads and resemble the type of fitting used on modern day air compressor (an air 'chuck' type fitting) then you have an R134a fitting. If you have 'air chuck' type fittings attached over 1/4 inch male flare fittings, you have a system that has been converted from R12 to R134a (keep in mind that the specially designated fittings for some alternative refrigerants bear similar resemblence to R134a fittings, but R134a guages will not attach to them). Also, keep in mind two things. Refrigerants that contain ANY amount of flammable substance(s) (such as Freeze12, HCFC12, AutoCool and others) are illegal in most states. Refrigerants other than R12 and R134a void warranty on most parts produced by most manufacturers (and, yes, they do test, and yes, they can tell). Additionally, you might note that these alternative refrigerants (ANY BLENDing of refrigerants is federally illegal) are generally more expensive than R134a. Given the ease of converting a system now and the low cost of R134a, and the items mentioned above... why use something else? And I didn't even mention the fact that no one has done extensive research on these alternative refrigerants to determine what, if any damage they might cause to a system and/or what type of oils are compatible with them.
The pressure of R-410A is significantly higher than other refrigerants R-22 and R-404A. This does not mean that R-410A, or equipment containing R-410A is unsafe. It does mean that technicians must use AC equipment; cylinders and service tools have been re-engineered to handle these higher pressures.
Yes
"Freon" is a trademark name of DuPont for a series of HFC and CFC refrigerants which they manufactured - other companies manufactured and continue to manufacture the same refrigerants, but cannot use the name Freon for their product. Some of the refrigerants marketed under the name Freon are flammable, and some are not. The CFC refrigerants will almost certainly be flammable - the HFC refrigerants may or may not be.
Freon was replaced by other refrigerants long ago.
R134a, just like any other vehicle for that model year.
It is absolutly the same r134a Is r134a no matter how u look at it. But be careful the stopleaks and oring conditioner in the small. Over the counter cans cam be harmful to refrigeration equipment other than cars it's the additives in the refrigerant not that specify it's use I have used the smaller cans in a pinch to fix small refrigeration equipment but I buy the can that is free of the automotive additives(ussually the cheapest one on the shelf) unless I'm using it in a car
The Waste Electrical and Electronic Equipment (WEEE) Directive aims to prevent the generation of electrical and electronic waste and to promote re-use, recycling and other forms of recovery in order to reduce the quantity of waste discarded. It requires the collection of waste electrical and electronic equipment and the recovery and re-use or recycling of waste collected.
The Waste Electrical and Electronic Equipment (WEEE) Directive aims to prevent the generation of electrical and electronic waste and to promote re-use, recycling and other forms of recovery in order to reduce the quantity of waste discarded. It requires the collection of waste electrical and electronic equipment and the recovery and re-use or recycling of waste collected.
Your car should use R134a. The manufacturers switched in the early 90's. The easy way to tell is have a look at the sticker under your hood. Every car I've looked at has a sticker that says some basic emissions data, engine size, and the type of refrigerant used. The other way to tell is to look at the two charge ports. You'll find them on the silver coolant lines, under large plastic plugs that look like tire valve caps. R134a systems will have a quick disconnect fitting (a ridge, not a thread). R12 will have threaded fittings for the hose. If you have a car that uses R12, it should be converted to R134a. The process isn't very hard, and the parts are available at most auto parts stores, if you have a vacuum pump and recovery unit. A R12 to R134a conversion kit comes with fitting converters, a flush kit (you can NOT mix R12 and R134a. Bad things happen to your equipment), and the recharge freon and oil.
You need to have the licenses to purchase any of the refrigerants you specify. Just the A/C Licenses is not enough. There is special training necessary to get the proper EPA permits to purchase and handle them.