Need help recharging a/c system with R-134.

[LMT32]

I have a '93 Cadillac Sedan Deville and I want to recharge the a/c system with the R-134 freon. The car has an electronically controlled ventilation system which disables the a/c function from turning on if there's not enough freon in the system. Will I need some special equipment to make the computer turn on the a/c function so I can recharge the system?

Thanks for any assistance.

[Klr Ontherd]

If you are currently with the R12 then you will need to have your system converted to use the R-134.

Check out this thread here:

http://caddyinfo.ipbhost.com/index.php?showtopic=6187

Should be enough info. The links there are informative as well.

[KHE]

If you have a leak in the system, you will need to repair it first as R-134a will leak faster than R-12. Why not stick with R-12??? The price of R-134a is EXPENSIVE these days.

IN order to properly retrofit to R-134a, you must remove the compressor and flush the mineral oil out of it with PAG oil. Next, you will need to flush each component individually. The old tube and fin condensers can be flushed easily unlike the more modern parallel flow types. You will need to remove the condenser and lay it flat while flushing in order to thouroughly remove all the old oil.

The accumulator must then be replaced as it retains a significant portion of oil and to get a fresh dessicant into the system. All the connections will need new o-rings to be sure they properly seal. Add the remaining quantity of PAG oil to the accumulator - ie if the compressor took 5 ozs and a full charge of oil as specified on the accumulator label is 8 ozs, add 3 ozs to the new accumulator.

Next, the system must be evacuated with a vacuum pump in order to remove all traces of moisture. Charge the same amount of R-134a as what's specified for R-12 or the low refrigerant code will set......

Now, after all that work, the vent temperatures will be 5 to 7 degrees warmer with R-134a at idle vs. R-12.......

If it were my car, I'd keep it R-12 as long as I possibly could - there is plenty of R-12 stockpiled in the US to last for many, many years.

[Klr Ontherd]

If it were my car, I'd keep it R-12 as long as I possibly could - there is plenty of R-12 stockpiled in the US to last for many, many years.

Currently in the United States, there is an estimated supply of 80 million to 150 million pounds of R-12. The auto industry will use about 35 million pounds this year alone, and refrigerators and residential air conditioning will use 25 million pounds this year. The R-12 currently available may be used up in the next two to three years.

Then once thats gone, we all know what will happen to the cost of conversion.

Blammo!!!! Right through the roof!!!!!!! Only because there will be no other alternative. Fork over the cash or sweat your gonads off

[KHE]

Currently in the United States, there is an estimated supply of 80 million to 150 million pounds of R-12. The auto industry will use about 35 million pounds this year alone, and refrigerators and residential air conditioning will use 25 million pounds this year. The R-12 currently available may be used up in the next two to three years.

Then once thats gone, we all know what will happen to the cost of conversion.

Blammo!!!! Right through the roof!!!!!!! Only because there will be no other alternative. Fork over the cash or sweat your gonads off

Most residential air conditioners (central air conditioners) use R-22 which is still relatively cheap although it is on the rise. Some window units use R-12 but when they go bad, most people have the throw away mentality and just buy a new one. The new window units either use R-22 or one of the new refrigerants.

Older refrigerators use R-12 but with the throw away mentality of today, who would even replace a compressor on a refrigerator? Many newer refrigerators and freezers use R-134a.

Stationary units use a completely different design of compressor than a motor vehicle. The compressors are sealed - there is not a shaft seal to go bad to vent the refrigerant. Plus, there is nowhere near the vibration or troublesome connections in a refrigerator like a motor vehicle system. Also, all refrigerant must be recovered/recycled so even when service work is performed, little to no refrigerant is lost.

As far as cars are concerned, the demand for R-12 has fallen off in recent years as most people don't want to spend the money repairing the air conditioning on a 12 year old car as many times the car is a beater by that point....(my Fleetwood Brougham is an exception. I have a case of R-12 on the shelf just in case.

30 pound cylinders of R-12 used to sell for $750+ a few years ago but now can be purchased for $350.....

[LMT32]

Thanks to some aid in one of the replies to my post, I finally found out that I was supposed to disconnect the negative post from the battery for at least 5 seconds then reconnect it, start the motor, then quickly connect the freon to the low pressure port and charge the system. I did all this and it appears to be a success because after charging it with just 2 cans, the a/c was blowing out some pretty cool air inside.

So I just want to appreciate everybody who took time out to help me find out what I needed to do to charge my car's a/c system. Thank you all!