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84 El Camino converting to R134 Questions

realtycaffeine on Fri April 06, 2012 10:10 PM User is offlineView users profile

Year: 1984
Make: Chevy
Model: El Camino
Engine Size: 350
Refrigerant Type: R134

I am converting this car over and want to make sure I don't screw this up. New compressor (4 seasons), new accumulator, new orifice tube, system flushed and ready to draw a vacuum and refill.

How much oil do I add to the new compressor? I have the right oil and the R134 freon to put in but can't find out how much to add? Do I add to the compressor, accumulator, lines, or where?

How much vacuum to pull and how long to hold the vacuum before adding the freon?

Any tips or online resources to read before I do this would be greatly appreciated.


Jerry Robertson
1984 El Camino

bohica2xo on Sun April 08, 2012 2:56 AM User is offline

My book says 8 ounces of PAG 150 for the R4 compressor in that car.

Put as much of the oil as you can in the compressor inlet, and put the rest in the accumulator. Make sure you turn the compressor input shaft a few turns after you close the system up.

Evacuate for 15 minutes after you see 25 inches of vacuum. With the pump running, close both handwheels on the manifold. The vacuum should hold. Shut the pump down. Wait at least 30 minutes for the oil to outgas and the water to boil off. Check the gauges again, you probably will see some loss of vacuum.

Re-start the pump, then open the handwheels. Evacuate for another 15 minutes, and shutdown as before. Wait 30 minutes again. If there is no change in vacuum level, you are ready to charge.

With the engine stopped, and the system in vacuum it is best to charge as much of the charge as you can as a liquid through the high side before you begin running the compressor. If you are charging with cans you can usually get most of the first can in as a liquid. Connect the can & position for liquid. Open the high side valve and let it go in.

Be sure to close the high side valve before starting the engine. The high side valve should remain closed for the rest of the charging process.

Start the engine, and finish charging through the low side. Do NOT jumper any switches. If the system short cycles as you begin vapor charging that is just fine.


"Among the many misdeeds of the British rule in India, history will look upon the act of depriving a whole nation of arms, as the blackest."
~ Mahatma Gandhi, Gandhi, An Autobiography, M. K. Gandhi, page 446.

mk378 on Sun April 08, 2012 10:14 AM User is offline

Also before you start, drain out any oil that might be in the "new" compressor. Check the instructions that came with it about whether it was already filled. You don't want that oil, especially if it is mineral oil that only works with R-12.

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