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AC Charging Question


caddydude

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I've been searching the archives and in an earlier post KHE wrote you should hold the freon cans upside down when charging the AC system but the directions on my freon cans say that the can are to be held upright only using a large red arrow to emphasize the fact. The refrigerant is 134-a with no oil, system sealer or leak detector dyes. Should the cans be upright or not? Should I be using refrigerant with the oils and sealers? My system will have a new compressor, dryer, orifice tube and be completely flushed and vacuumed. I already put 4 oz. of Pag oil in the compressor and will be putting 4 oz. in the accumalator/dryer. I would appreciate any help. :blink:

Thanks!

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If you have the correct amount of oil don't add anymore and DO NOT add sealant (snake oil). If you try to add the refrigerant upright (as a gas) it will take forever. Turn the can upside down and add as a liquid. KHE is much more knowledgable than I about A/C. I'm sure he will agree with me. I am not sure what the correct amounts of oil are but am sure he will have them.

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If you have the correct amount of oil don't add anymore and DO NOT add sealant (snake oil). If you try to add the refrigerant upright (as a gas) it will take forever. Turn the can upside down and add as a liquid. KHE is much more knowledgable than I about A/C. I'm sure he will agree with me. I am not sure what the correct amounts of oil are but am sure he will have them.

The question that I have IS, how do you know you have the CORRECT amount of oil? Mike

Early on sailors navigated by the stars at night and the North star became the symbol for finding ones way home. Once you know where the Northstar is you can point your ship in the right direction to get home. So the star became a symbol for finding ones way home or more symbolically even finding ones path in life.

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Scotty,

Re: How to check A/C oil level.

I do not think GM has an actual A/C refrig oil level sensor, since the oil is distributed throughout the regfrigerant itself (ideally). Obviously, in a sealed system the oil stays around regardless of compressor wear (aside from complete destruction). If the freon leaks, most of the oil tends to stay because it is not a gas (might drain a bit from a low point leak though).

As I recall (please confirm) from other posts, the entire A/C system has to be evac'ed and the hoses, equip blown/drained and retained to measure the remaining oil. Then the hoses should be cleaned with mineral oil (if metal shavings or any other residue suspected), blown out again, evac'ed and recharged (whew...). Of course, these A/C jobs can only be accomplished during the hottest, most humid days at the worst possible timing (no parts shops open and trip tommorrow) ;)

Considering the PITA factor, that is why so many post advice to not add oil (or snake sealants), unless you are very certain that it really needs it, which again is da*m difficult to determine accurately. <_<

Home and Industrial A/C is really so much simpler (and you can actually get to almost everything)...

Good luck :)

Add power to leave problems behind. Most braking is just - poor planning.
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Scotty,

Re: How to check A/C oil level.

I do not think GM has an actual A/C refrig oil level sensor, since the oil is distributed throughout the regfrigerant itself (ideally). Obviously, in a sealed system the oil stays around regardless of compressor wear (aside from complete destruction). If the freon leaks, most of the oil tends to stay because it is not a gas (might drain a bit from a low point leak though).

As I recall (please confirm) from other posts, the entire A/C system has to be evac'ed and the hoses, equip blown/drained and retained to measure the remaining oil. Then the hoses should be cleaned with mineral oil (if metal shavings or any other residue suspected), blown out again, evac'ed and recharged (whew...). Of course, these A/C jobs can only be accomplished during the hottest, most humid days at the worst possible timing (no parts shops open and trip tommorrow) ;)

Considering the PITA factor, that is why so many post advice to not add oil (or snake sealants), unless you are very certain that it really needs it, which again is da*m difficult to determine accurately. <_<

Home and Industrial A/C is really so much simpler (and you can actually get to almost everything)...

Good luck :)

Thanks, I need to change my compressor and accumulator next weekend and was considering purging out all the oil and installing the correct amount of oil in the system since I DO NOT know if simply adding the required amount of oil for the compressor and accumulator will be adequate. This unknown bugs me. Any Ideas about my concern? Mike

Early on sailors navigated by the stars at night and the North star became the symbol for finding ones way home. Once you know where the Northstar is you can point your ship in the right direction to get home. So the star became a symbol for finding ones way home or more symbolically even finding ones path in life.

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Here's what the "good book" says.

System holds 8 oz.

Component replacement:

Compressor - 2 oz.

Accumulator - 1 oz. more than was drained

Evaporator - 3 oz.

Condensor - 1 oz.

If an abrupt loss of refirigerant was experienced add 3 oz.

Slow seepage does not require adding oil

If possible add oil to component being replaced. If unable add to the accumulator.

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Don't use any refrigerant cans with stop leak or o-ring conditioner. The o-rings don't need to be conditioned and if there is any leak in the system large enough to affect cooling performance, the stop leak won't repair the leak.

I always charge as a liquid - with the can upside-down in GM cars as the low side charging port is on the accululator. Any liquid refrigerant vaporizes instantly in the accumulator so it won't slug the compressor. You can charge as a gas but it will take much longer.

Any other A/C systems, it's best to follow the advice in the shop manual.

Mike - just add the required amounts of PAG oil as specified in Larry's post and you'll be fine. There is no real way to tell how much oil is in the system without draining the system, flushing each component with solvent, and then adding the proper amount of refrigerant oil specified on the accumulator/in the shop manual - PITA and usually not necessary.

You can have too much oil in the system - that will be hard on the compressor and will result in poor cooling.

Kevin
'93 Fleetwood Brougham
'05 Deville
'04 Deville
2013 Silverado Z71

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I might add: I replaced my compressor with a reman delco unit. The unit was shipped sealed and full of oil. I drained the oil and flushed it with fresh oil . I was SUPRISED at the condition, color, crud that was in the delco remanned compressor. I did the flush twice so that the oil was fresh and clean, coming out, as it was in the bottle. I then filled the compressor with the proper amount of oil and added the rest to the accumulator. Peace of mind for me...

rek

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