Converting an R-12 system to R-134a is a little more complicated than simply having the R-12 recovered and replacing it with R-134a. Most people (especially with vehicles old enough to still have an R-12 system) don't want to put in the money it would take to do a proper conversion to R-134a. So they replace the compressor oil, seals, and fittings, and leave it at that. Which is sufficient.
R-134a is slightly less effective than R-12, but it works. System pressures will be higher (which is why parts need to be replaced when converting to R-134a). It's much less flammable than R-12, considerably less toxic, and it does what it's supposed to.
AC systems are not DIY work. The refrigerant has to be recovered, and you're also going to want to do a system performance test both before and after the conversion to ensure that there are no leaks or other deficiencies with the AC system.
R134 .... IS freon.
The newer Freon (r134) does not mix with the old Freon. The system needs to be flushed, special oil added so that r134 will be compatible with the system gaskets, then a vacuum pulled. Then the Freon can be added.
R134
AnswerNO! The problem is that the lubricating oils are not compatible, and the mixture will clog the system.
Only if you're trying to destroy your AC system. Never mix refrigerants.
To convert an R12 system to R134 all of the R12 will have to be removed. The system will have to be completely flushed out then special additives installed. This is done due to the way the different Freon's react to the systems gaskets. After this is done then the system is ready to be set up with new Freon.
The 2002 ford Ranger uses type R134 Freon. The Freon is added in the low pressure port of the ac system.
3.7lbs
You do not want to buy Freon as it is very, very, expensive. Have the leak repaired, the system purged of all Freon R12 and the oil. Have it converted over to R134 refrigerant. You cannot just add R134 as the oil used in R12 is not compatible with R134. You will be money ahead by converting it.
R134
THERE IS NO FREON IN A 98 IT IS R134
They should never be mixed.