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A/C time ...how to handle refridgerant

Old 05-28-2018, 08:23 AM
  #16  
PorscheFanatic202
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Remember. Do it once and do it right. No shortcuts. If you don't know what was filled into the system, flush it and start over. If I am not mistaken, the oils for each refrigerant are different.
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Old 05-28-2018, 05:42 PM
  #17  
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Let’s say I replaced the one AC line and then wanted to “start over”.

Can a liquid AC flush be performed at home? If not, would the vacuum not pull out any oil?
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Old 05-28-2018, 05:46 PM
  #18  
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Oh, and what would happen when I recieved the new AC line? Do I simply undo the old one and install the new one? If the system has residual charge, is there a procedure to disconnect the line?

This stuff is under pressure, correct?

I’m thinking of replacing the obviously worn out line as a first step before buying the vacuum. Just want to see if that gets the AC going (filling up with my extra can of R12a)
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Old 05-28-2018, 05:59 PM
  #19  
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This stuff is under pressure, correct? You have to check to see if there is refrigerant in the system.
You can't replace a line if there is refrigerant in the system.
If there is no refrigerant in the system you can replace the line.

Can a liquid AC flush be performed at home? Yes, if you follow the procedures and have equipment.
If not, would the vacuum not pull out any oil? No.
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Old 05-28-2018, 08:09 PM
  #20  
Tom M'Guinn
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Originally Posted by griffiths View Post
If not, would the vacuum not pull out any oil? No.
Please don't think I don't want to not say I'm not confused, but just to confirm: you are saying a vacuum would pull out some oil, correct? It seems like that's about all we can hope for these days even at decent shops...

(Just kidding a bit, always appreciate your posts here. My car is cool as a cucumber thanks to you all.)
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Old 05-28-2018, 10:51 PM
  #21  
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Alright.. first step then is to attach the guage that came with the diy kit onto the low side connector to see if there’s any refrigerant left. I assume that one guage should be good enough to show any pressure in the system, yes?

And if anything shows, then.... notwithstanding any legalities.... what would happen if someone pushes the little plunger in the connection, much like releasing air from a tire? Is there a possibility of harm to person or vehicle from this action?

Perhaps most importantly.... why would Porsche put the low side connector at the bottom of the car and the high side connection more conveniently at top of the engine compartment? This is a serious question! Is AC service action supposed to happen at the high side?
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Old 05-28-2018, 10:55 PM
  #22  
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Originally Posted by Tom M'Guinn View Post
Please don't think I don't want to not say I'm not confused, but just to confirm: you are saying a vacuum would pull out some oil, correct? It seems like that's about all we can hope for these days even at decent shops...
Shops suck the oil out with a vacuum which apparently can’t be done? Now I’m the confused one! lol
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Old 05-29-2018, 06:30 AM
  #23  
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Oil doesn’t typically evaporate, therefor it cannot be removed using the vacuum pump used to evacuate the AC system.
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Old 05-29-2018, 08:03 AM
  #24  
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Originally Posted by Dan Martinic View Post


Shops suck the oil out with a vacuum which apparently can’t be done? Now I’m the confused one! lol
Okay, I TRUMPED you. I told a little white lie.
Let's rephrase it.... the only oil that will come out will be oil adjacent to the service ports.
Any oil that is below the line of gravity, far, far away, in the drier, in the condenser, in most of the hoses and bottom of the compressor..... will not genie out of the bottle.
Depending upon the year, make and model of a vehicle, you might get a 1/10 of a fluid ounce or an ounce at worst.
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Old 06-04-2018, 11:55 AM
  #25  
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Originally Posted by griffiths View Post
Okay, I TRUMPED you. I told a little white lie.
Let's rephrase it.... the only oil that will come out will be oil adjacent to the service ports.
Any oil that is below the line of gravity, far, far away, in the drier, in the condenser, in most of the hoses and bottom of the compressor..... will not genie out of the bottle.
Depending upon the year, make and model of a vehicle, you might get a 1/10 of a fluid ounce or an ounce at worst.
Perhaps this is why the low side port is at the bottom of the engine. I spoke with a home HVAC guy who suggests flushing won’t get the oil out; he said to “make a hole” at the lowest point in the system and let it drip out, then restart.

He said mechanics call him all the time and there isn’t really dedicated places anymore.

If I replace my busted rubber line, can I run a temp fill of some oil/charge combo to test for any other leaks?

Oh: the HVAC guy said compressors are “hermetically” sealed and impossible to leak out (!)

There is much confusion out there!
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Old 06-04-2018, 12:03 PM
  #26  
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I just realized that the line I’m changing connects to the condenser, at bottom I think; I also bought a new drier. Maybe I’ll get most of the oil out by replacing those things and pulling a vacuum on the low port.

Then, I can fill with R134a and just use the chart values for the oil? Can it be so simple?
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Old 06-04-2018, 12:23 PM
  #27  
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Originally Posted by Dan Martinic View Post

Oh: the HVAC guy said compressors are “hermetically” sealed and impossible to leak out (!)






STOP RIGHT THERE.
You are having discussions with a hvac technician that does NOT have any experience whatsoever with auto AC .

1) Auto AC compressors driven by belts are not hermetically sealed.
2) You cannot suck out refrigerant oil from the system that is not adjacent to the service port; you can pull that mass over a hill.
A vacuum simply reduces the pressure in the system below atmosphere.
3) Auto ac systems can be flushed (condenser, hose lines, evaporator with TEV removed; but not compressor, or drier), if you know what you doing.

Last edited by griffiths; 06-04-2018 at 12:57 PM.
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Old 06-04-2018, 11:16 PM
  #28  
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It seems the oil thing is what keeps this from an easy DIY project

What's a TEV?

In this video, the mechanic replaces a compressor. While out, he "drains" it of oil then puts in an amount he found "the compressor takes" (4 oz)


If even a flushing can't remove the oil from the compressor, it would appear that, since I have no idea what is in this system, to start over I'd have to not only flush the system but remove / drain / re-fill the compressor too, correct? Not too big of a deal, just a step that could be easily overlooked.

I wonder if I took it to a proper AC shop (if one exists locally) for a "flush & fill", would they actually remove and replace the compressor....
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Old 06-05-2018, 08:05 AM
  #29  
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Expansion valve (attached to the evaporator), acronyms used are TEV, TXV or TX.
TEV = thermal expansion valve.
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Old 06-05-2018, 09:20 AM
  #30  
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Attached to the evaporator? The part that's inside the dash?

A couple of years ago I had the evaporator changed.. at a very steep cost to my wallet and some dash trim; should have done that myself.

But to flush the system, I'm not sure I want to take all that apart. Tell me that isn't the procedure?
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