A/C replacement - Need Help

[USA-86]

On my 86 coupe I will be replacing the compressor with clutch,new drier and a new orrifice tube. My question is how much oil will be required. My FSM indicates 2.75lb of R-12 but nothing about how much oil for a new system.

 

[CharlesBrown]

Are you sure you want to use R-12? This would be a good time to update your system to R-134a. I've seen R-12 priced as high as $75/can and I believe in some states it’s illegal. When this was done to my vett all they had to do was change some fittings and, of course, draw down and refill the system. I've heard there is also a "Freon" that simply replaces the R-12 with the newer stuff but it's not recommended. I've noticed little difference in cooling the cabin with the conversion!

 

[Lucky 3]

The last compressor I changed had a yellow sticker on it that said 8 ounces of oil. But it was a 134A system.

 

[Ugolino]

Lucky3 is correct, it is 8 oz of oil for a completely evacuated and flushed system, whether the system is R12 or R134a. I would usually put 2 oz of oil each in all four parts: accumulator, evaporator, condenser, compressor, for a total of 8 oz.

 

[Rex S]

If the system had Ester oil, used with R12, it MUST be flushed befor PAG type oil is installed with a fresh charge of 134A. Lines, condenser and evaperator.

 

[rlg]

If the system had Ester oil, used with R12, it MUST be flushed befor PAG type oil is installed with a fresh charge of 134A. Lines, condenser and evaperator.

If it has ester oil it is compatible with all freons.

The original R12 used mineral oil and the new 134 uses the pag type.


Don't mix them.

 

[kalmwill]

If you change to 134a you must also change the accumulator. Otherwise the bags containing the moisture absorbant will burst and cause damage to your compressor. I speak from personal experience with an old Caddy. I have been using HC12a in my system for the last 3 years and it has been working very well. I flushed the system completely and used synthetic AC oil with the HC 12a. I only needed 40% of the recommeded original R12a freon.

 

[tonylong]

If you change to 134a you must also change the accumulator. Otherwise the bags containing the moisture absorbant will burst and cause damage to your compressor. I speak from personal experience with an old Caddy. I have been using HC12a in my system for the last 3 years and it has been working very well. I flushed the system completely and used synthetic AC oil with the HC 12a. I only needed 40% of the recommeded original R12a freon.

I'll be rebuilding my 89 vert's AC this summer what is HC12A, I thought my only choices were R12 or 134?

 

[kalmwill]

HC12a is a propane butane based coolant. It is manufactured in Canada by Duracool Duracool®.com 2004 - Duracool® is The Recognized Leader In Hydrocarbon Refrigerant Technology and in the US by a company called HC Refrigerants HC Refrigerant. I'm sure that there are others as well.
The problem with R12a is that it is ozone depleting, but it is a very good coolant. R134a is not as good a coolant with smaller molecules that can leak more easily. The oil that goes with it becomes acidic if it comes in contact with moisture in the system. The acid attacks the aluminum components of the air conditioning system, evaporator etc. What I have determined is that the HC12a is inert, and the synthetic oil that you can purchase is not moisture absorbing and does not cause damage to the aluminum components. It is also a very good coolant. If you visit the Duracool web site they offer a lot of information, only remember that it is a company web site which would obviously be biased in favour of their product. I hope that this helps and does not muddy the issue too much.

Cheers

Bill

 

[Rex S]

Bill, while you are correct about Duracool's web site pushing their product, HC based refrigerants will soon be the new standard by the EPA as 134a is about to be phased out.

 

[kalmwill]

I didn't know about the EPA information but it does make sense to me. I did much research on coolants a number of years ago and decided to give the HC12a a try. I have had it in three vehicles for a number of years, including my 86 Vette, and can say that it is a very good coolant that works very well.

Bill