A/C Recharging

Jeff Lukaszek

Active Member
After a full restoring my 1963 Buick Wildcat I am trying to recharge the a/c. Does anyone know how much A/C oil and Freon it should take for this vehicle. I have the manual but did not see the amounts unless i just missed it.

Thanks Jeff

Jeff Lukaszek

Active Member
The system was working when I took it apart. It's not a new compressor Its the compressor that was on the car. So when it is drained will it loose all its oil?
Jeff; Tom is correct and the oil is critical to keep the compressor lubricated. If the manual says 10 1/2 ounces of oil, you should;
1. drain the new compressor and measure what comes out.
2. In theory the other A/C components should also be drained, (condenser, evaporator, reciever/drier(dehydrator) and lines) and then you can start from the beginning.
3. Ideally the oil should be proportioned out through the system and I would start with putting 5 ounces into the compressor, then 2 ounces into the condenser and 2 ounces into receiver/drier. The final 1 1/2 ounces should go into the evaporator.
4. This would ensure that the oil has been distributed through out the who system. Overfilling the compressor which most people make the mistake of doing, could damage seals inside the compressor. The oil will not distribute itself around the system if loaded into one place.
A good repair/workshop service centre who have an A/C machiine will suck the freon and oil out of your own system for free as they can then reuse it. Was the components in this system disconnected and the freon and oil lost and if so you will need to start the process from the beginning. If the system was not disconnected, you may be able to top it up?
What freon are you going to use R12 or R134A?
Take care and keep us informed as to how you got on.
BCA #46404.
ROA #15353.
No, it will not. Oil circulates through the system along with the refrigerate when operating.
An approximation is:
1 1/2 ozs. in the A/C condenser, approx. 1 oz. in the evaporator, approx. 1 oz. in the accumulator/drier, approx. 1 oz. in all the hoses & piping for a total of 4 1/2 ozs.
Remove the drain plug on the compressor & put into a measured container. IF in good condition it will be pretty clean/clear. IF it's dirty it's time for a flush of the system OR there could be other problems. IF the system holds approx. 10 1/2 ozs. minus the above approx. calculations add the remaining required to the compressor.
These are all approximations. NOTHING is written in stone as far as these calculations go.
Why do you think A/C compressors go bad in the 1st. place??? Because over the years MANY, including shops, just add Freon but don't replenish the lost oil. After a period of years the system runs low/out of the proper amount of life supply of oil.
Freon is lost normally through hoses, O-Rings, seals, etc. Normally everything is OK for the 1st. 3 yrs. After that it normally becomes a
yearly/bi-yearly thing.

Just my thoughts on the subject at hand.

Tom T.

While i was responding John ALSO responded before I actually got to post. We do agree pretty closely.
It is the manual on the site here: Air Conditioner, 1963 Buick Chassis Manual, Special
Air Conditioner Specifications:
Oil, new 10-1/2 ounces
Capacity, 2-1/2 pounds

Do you know if the compressor is empty? New compressors are often supplied with oil in them. It isn't a bad habit to add a couple of ounces anyway.

The capacity on the Wildcat is 10-1/2 oz oil and 4 lb Freon. Reference is pg. 11-38 of the full-size Chassis Service Manual.

The 2-1/2 lb Freon capacity is for the compact Special cars.
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I would remove the compressor and drain the oil out of it and replace it with the correct amount of oil. You can still buy the correct compressor oil on Amazon when I last looked a few months ago. I keep a supply of oil that matches up to my supply of refrigerant. One is no good without the other. I would also replace all the "O" rings with new Viton "O" rings while you are doing the servicing. You should also replace the receiver / drier right before you are going to complete the servicing. I have done many an air conditioning service using R12, and I never install refrigerant into a system until I am absolutely certain that I have addressed every possibility of a leak. This means new O rings, cleaning of the evaporator coil on the outside, and cleaning the condenser also. If I am not certain of the system's condition, I also purge each component separately with a cleaning agent meant only for air conditioning. Once all this is done, I will draw a vacuum on the system, and I like to get it down to at least 750 microns and see that it will hold the vacuum for a minimum of 1 hour. Then I will charge the system with nitrogen to check for leaks under pressure. Only after I know that it holds pressure for at least an hour, I will evacuate the nitrogen, charge it with R12, and install about 85% of the total that the service manual specifies. At that point, I will start the car and run the system while watching the site glass for bubbles. I will add refrigerant in small amounts till there are no more bubbles in the sight glass. Usually, I will see a thread going across the site glass, but if I am getting good cooling inside the car, I just stop. I use a 30-pound cylinder of refrigerant and a refrigerant scale to know exactly how much I have installed. If you are using 12 or 14-ounce cans, you can keep track of the quantity by doing the math. I always install the metal caps, and this year I learned about a product that helps to stop leaks from the Schraeder valves. It is called " Nylog Blue ". You put a drop or two onto the threads of the metal service port cap and then screw it on hand tight. Then give it a slight tweak with your socket to seat it, and it will stop leaks from the service port valves. It only works with the metal caps.


Active Member
Use the original mineral oil if you are going to forever use R-!2. Use ester oil if you might later change to a modern refrigerant like R-134a, R152a or some of the blends. Use pag oil if you have a new and clean system and will use modern refrigerants. I like ester oil because it will mix with any remnants of mineral oil and not separate and can be used with R-12 or modern.