Toyota MR2 Message Board - View Single Post - New A/C compressor R-12 to R-134 Ideas?

emar2 · 05-25-2007, 06:35 PM

To see if there is any freon left in the system find the access ports on the front bulkhead. They are like tire valve stems, so just press one down to see if you get a release of gas. Do not have your face directly over the valve when you do this

. If you get nothing, then the system is already empty. I am an HVAC tech, andd in my opinion you are asking for headaches if you take apart a non leaking system. The main difference between R-12 and 134A as it pertains to the o-rings in the lubricating oil used in the systems. The oil used for 134A is a synthetic that damages the R-12 O-rings, which were designed for mineral based oil. The R-134A conversion kit includes oil that is both non-reactive to the R-134A as well as the R-12 O-rings. If you properly flush the system, you should have no problems. If you can put a vacuum to -30 mmHg on your system and it holds for 30 minutes with the pump turned off, you have no leaks. The rubber in the O-rings on the car are not exposed to air or sunlight, only freon and oil they last a really long time unless the fitting has been opened. Definitely replace the orifice tube and drier when you do the compressor. You will void any warranty if you don't and they are likely clogged with debris from the old compressor failure. Sorry for the long post, but I hope this helps and good luck.

05-25-2007, 06:35 PM	#3 (permalink)
emar2 '87 NA T-bar; '88 FX-16 Join Date: May 2007 Location: Phoenix AZ Posts: 13 Thanks: 0 Thanked 1 Time in 1 Post iTrader Rating: (0/0% )	To see if there is any freon left in the system find the access ports on the front bulkhead. They are like tire valve stems, so just press one down to see if you get a release of gas. Do not have your face directly over the valve when you do this . If you get nothing, then the system is already empty. I am an HVAC tech, andd in my opinion you are asking for headaches if you take apart a non leaking system. The main difference between R-12 and 134A as it pertains to the o-rings in the lubricating oil used in the systems. The oil used for 134A is a synthetic that damages the R-12 O-rings, which were designed for mineral based oil. The R-134A conversion kit includes oil that is both non-reactive to the R-134A as well as the R-12 O-rings. If you properly flush the system, you should have no problems. If you can put a vacuum to -30 mmHg on your system and it holds for 30 minutes with the pump turned off, you have no leaks. The rubber in the O-rings on the car are not exposed to air or sunlight, only freon and oil they last a really long time unless the fitting has been opened. Definitely replace the orifice tube and drier when you do the compressor. You will void any warranty if you don't and they are likely clogged with debris from the old compressor failure. Sorry for the long post, but I hope this helps and good luck.