We have a 1992 Cadillac hightop 6 door limo. We need to know how much freon to fill the a/c system. Where it is a conversion we know that it takes more than a regular car but we dont know how much, can someone please help us with this. Thanks in advance.
Need help
- Thread starter Mark C New
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In the front of the car is the condenser, and there is a receiver drier with a sight glass on the top where the lines enter the condenser. I would look at the sight glass after adding the specified amount of oil to the compressor, and add 3 additional ounces to the compressor for the rear air conditioning unit. Charge the system on the low side until you see all the bubbles in the sight glass disappear. Sometimes you will see a fine thread of refrigerant moving through the site glass, and that is normal. If your cars original system was charged with R12, and you are converting it to R134, there are additional items that need to be removed and changed to accommodate the R134 in a R12 system. I have never done a conversion, and I can't advise you exactly what changes will be necessary. 1992 was the year that R134 was introduced, but not all car manufacturers made the change from R12. You need to have a factory shop manual, and start by using the amount of refrigerant for the basic car, and then adjust up from there.
Already been converted, to r134a, On a 1996 car the freon is 28oz, on a superior limo, its 4lbs., My 1992 doesn't have a conversion sticker for when they turned it into a limo. Now they put the new specs, but evidently we got a superior that don't have it. We contacted a hearse dealer and they have a 1990 6 door and it worked perfectly at 4lbs. 12 oz....but I also know that if you overfill it can do more damage than underfull.
Just following up on this discussion. When a R12 system is converted to R134, the rule of thumb is to use 80% of the original quantity of refrigerant. There are some additional modifications that need to be done to the system to allow the system to give satisfactory results. The Evaporation Air Conditioning Orifice Tube is one item that is usually changed, and I don't remember what the other item is, but most shops that do this type of work will be familiar with the conversion process.
As to the specific amount of refrigerant, the best method to determine this is to watch the sight glass for bubbles during the filling process, and once the bubbles are no longer visible, you should stop filling. I have a refrigerant scale that I use, and it weighs the amount of refrigerant as it is being removed from the steel bottle, and when you are done, you will know exactly how much you put into the system. You should make a note of this in the permanent record of the vehicle, should you need to charge the system in the future.
As to the specific amount of refrigerant, the best method to determine this is to watch the sight glass for bubbles during the filling process, and once the bubbles are no longer visible, you should stop filling. I have a refrigerant scale that I use, and it weighs the amount of refrigerant as it is being removed from the steel bottle, and when you are done, you will know exactly how much you put into the system. You should make a note of this in the permanent record of the vehicle, should you need to charge the system in the future.