I need some help for charging my factory a/c system. Can somebody give me some informations about the amount of refrigerant (r134a) and oil, which should be in the system. And what kind of oil I should use?
Thanks a lot and best regards from germany
Well it took me a while to find my notes.
my 1969 Cougar notes say it takes 2 3/4 pounds of R12.
With that said, the following table shows the amount of R134a to replace a given amount of R12.
The second page gives instructions about the compatible oil and such.
My 1968 with Tecumseh compressor and stock 1968 system has been cooling well with 27 to 28 ounces, or 0.78 kg, of R134a. My mechanic friend and I didn’t want to overfill and stopped when we got a nice, cold output.
The placard on the compressor for 1967 - 1970 says 1 3/4 pounds of R12 refrigerant. That’s what I use and it seems to be plenty. I think I would convert 1 3/4 to R134 using the table to avoid overcharging / locking up the compressor.
How much oil is recommended for a good charging?
Thanks a lot for your great support.
Just to verify. Your system has been converted from R12 to R134A. Correct?
If your system has not been converted and still has R12 in the system and the drier has not bee replaced… you’ll be in for a very rude learning experience.
It’s also not a bad idea in your situation to find some r134 with fluorescent dye, so that if it leaks out you can find the leak with a UV light. It can be very helpful for really almost no extra money. Properly operating AC systems don’t consume refrigerant or require topping off, so you likely do have a leak.
Remember to pull a good strong vacuum and hold for 30 minutes… that’s another leak-check, although not foolproof. Some leaks won’t appear under vacuum but will under pressure.
Yes, my system is completly new and converted to r134a. I will do the charging with a a/c machine, because the machine tests the vaccum and hold it for 30min. The machine adds a fluorescent dye and the oil, but how much oil I must fill into the system?
Yes, I stand corrected, The tag on my 1969 compressor reads the same, 1 3/4 pounds. gotta fix my notes.
Not knowing exactly what system you bought, it’s hard to say. Most aftermarket compressors come pre-filled with oil, in fact I have never seen one that did not. However, that is just for the compressor, and the compressor manufacturer doesn’t know what sort of system the rest of the car will have. In your case I would call the manufacturer of your system and ask them for the total oil recommendation. You would then drain your compressor of the factory fill since you don’t know how much the manufacturer added, and add in the specified system amount. “Most” systems take between 4-6 oz of oil, and when you change out a major component like a dryer or condenser it’s recommended that you add an oz of oil back in. Also make sure it’s r134 compatible oil. If your system is entirely new and all traces of the r12 mineral oil are gone, you can use a PAG oil.
I’ve learned a lot about AC the hard $$$ way. I hope we can help you avoid the avoidable mistakes!
Thanks a lot for the great reply, I think that will helps me.
I rebuild the a/c like the factory system, everything is a original part. Condenser, evaporator, hoses and so on are all OE style.
The compressor is an OE style Tecumseh and he comes without oil inside.