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SimpleOne
New User
Apr 23, 2014, 12:30 PM
Post #1 of 9
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Hi All,
I have 1997 GC8 Subaru Impreza WRX (Australian Market), it has the stock 2.0L EJ20 turbo engine. It has approximately 260,000km's on it.
A few years back, the A/C let go with a loud bang on a really hot day. It lost all cooling capability within about 30 seconds. I never got around to looking at repairing it until now.
I'm assuming there was some sort of significant failure, like a burst pipe or significant o'ring failure. I checked the High and Low side valves, there is no R134a in the circuit at all.
Before I runoff and replace bits like receiver dryers, I need to find the leak. Is there a way that DIY person can do this?
I was thinking of using my air compressor at 30PSI on the low side, and 150PSI on the high side to help find the leak, maybe with the aid of some dye if necessary. Is there any reason I shouldn't do it this way?
Thanks
(This post was edited by SimpleOne on Apr 23, 2014, 12:32 PM)
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Discretesignals
Ultimate Carjunky
/ Moderator
Apr 23, 2014, 12:44 PM
Post #2 of 9
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Re: A/C Leak Finding
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The high and low side of the ac system are connected in the same circuit. When the compressor isn't running the pressures in the system are equal. You can add two different pressures to each side of the system, but both sides with have the highest pressure. Not sure how the evaporator would like having 150 psi inside it. You may want to stay around the 90 psi range.
You really don't want to use shop air because that air is full of moisture and will contaminate your system oil and drier. You can use nitrogen though. You may be able to hear large leaks or find them with soapy water.
Can you turn the front plate on the compressor? Have you checked all the rubber ac hoses to see if one had burst?
You may need to remove the compressor and drain the oil out of it. Inspect the oil for metal.
http://www.youtube.com/watch?v=P14wdmmgheE
Since we volunteer our time and knowledge, we ask for you to please follow up when a problem is resolved.
(This post was edited by Discretesignals on Apr 23, 2014, 12:50 PM)
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SimpleOne
New User
Apr 23, 2014, 1:43 PM
Post #3 of 9
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Re: A/C Leak Finding
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Hi,
Yep the front plate of the compressor will turn, and the electromagnetic clutch works if you trip the relay, so I assume (at this stage) the compressor is fine and just not operating due to the low pressure sensor. I've given the hoses a quick once over, but I'll have to do it more thoroughly by moving some bits and pieces out of the way, as I couldn't find any obvious failures during the quick inspection.
I'm not overly worried about the compressed air being full of moisture for two reasons, it's reasonably well dried and filtered air from the portable compressor since i use it for painting; and secondly because I'm going to have boil off any moisture with a vacuum pump before recharging the system, so that will deal with any new moisture as well.
I'll get a quote from a local A/C place for a nitrogen pressure test though, might be cheaper than buying the correct connectors to connect the A/C manifold to the portable compressor.
If I do end up testing it myself, I'll try using 30 psi and some soap and water and see what I can find.
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Tom Greenleaf
Ultimate Carjunky
/ Moderator
Apr 24, 2014, 2:05 AM
Post #4 of 9
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Re: A/C Leak Finding
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A 30 second leak down isn't going to be hard to find. Alone that could be easy or not but now you stated system has been empty for a few years so it's contaminated now.
Problem is the oil (PAG oils are a problem) and absorb moisture and worse become acidic and nothing but flushing it all out and starting all over is going to have a chance. Any part of the system that contained refrigerant is now at high risk of failure.
Price out all components and think if you want to fix this at all! Some parts cheap but hard to do like the evap is usually a royal pest in labor if it goes well at all dash parts may break just getting at it if needed.
Check but you might find this too costly for the age and mileage of the vehicle to be worth it,
T
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SimpleOne
New User
Apr 24, 2014, 2:34 AM
Post #5 of 9
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Re: A/C Leak Finding
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Thanks Tom, that's good information to know. Many of the lines in the A/C system are steel, but not everywhere. I suppose many of the o'rings might also have become more brittle.
Given that compressor has just been sitting there doing nothing for years, what sort of prognosis is there for that?
Is it likely that the compressor will be unusable, even if i replace the oil? (for instance is it likely that the bearings might corroded or something?)
It seems to turn freely, but that doesn't mean that bearings are necessarily in good condition, just workable, for a while at least....
I can get a compressor from a wrecker for a few hundred, but I'd need to buy a vacuum pump also, as well as refrigerant etc, plus replace any o'ring
and hoses, so I would say I'm looking at $500-$750 fix as a ball park figure if the compressor needs replacing. Not sure what a receiver dryer will set me back either....
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Tom Greenleaf
Ultimate Carjunky
/ Moderator
Apr 24, 2014, 3:19 AM
Post #6 of 9
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Re: A/C Leak Finding
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I think you can rent a vacuum pump and gauges when the time comes.
IDK what really happens to "O" rings but they could be fine. Oil in system as settled to assorted low spots and would circulate upon a proper charge up by listed weight - no guessing.
Compressor turns and doesn't have bearings like a wheel but rather bushings. It could be fine and hard to know without getting it going. It might make noise but should shut up fast when charged.
Driers have desiccant in them which is junk by now and always to be replaced with say a compressor replacement. Forget used or even rebuilt ones that have high failure rates. There's no bargains for A/C - buy the best or you risk the whole project all over again.
OK - find that leak. Bet you can hear that one. Already said but late now for this with moisture invasion which is in air no matter how clean or dry you think it's wet. A/C anything and moisture don't mix.
Read up top at the locked posts on just some fun facts about topic. It's not cheap and one wrong failure you risk the job so not for most people.
Back: Used is a no go. If you had an identical working car you could use those parts with new "O" rings and seals where they are.
Trouble with leak finding is you are NOT supposed to use refrigerant to find leaks. Nitrogen with a spit of R-22 is one way if sniffing out one with an electronic detector. Dye can be useful but if this blasts out a 30 second leak it would make a mess to confuse finding it or more than one.
Leak finding can be annoying and difficult. Some leaks don't leak unless under operating pressures so can be a rock and hard place.
You heard this one when it quit while in use. Check for a plain hole in the condenser from perhaps a rock or road debris that struck it?
T
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WyrTwister
User
Apr 25, 2014, 10:30 PM
Post #7 of 9
(2937 views)
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Re: A/C Leak Finding
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Thanks Tom, that's good information to know. Many of the lines in the A/C system are steel, but not everywhere. I suppose many of the o'rings might also have become more brittle.
Given that compressor has just been sitting there doing nothing for years, what sort of prognosis is there for that?
Is it likely that the compressor will be unusable, even if i replace the oil? (for instance is it likely that the bearings might corroded or something?)
It seems to turn freely, but that doesn't mean that bearings are necessarily in good condition, just workable, for a while at least....
I can get a compressor from a wrecker for a few hundred, but I'd need to buy a vacuum pump also, as well as refrigerant etc, plus replace any o'ring
and hoses, so I would say I'm looking at $500-$750 fix as a ball park figure if the compressor needs replacing. Not sure what a receiver dryer will set me back either....
Shop around , including on the internet . I just ordered a kit w/ compressor , o-tube , accumulator & o-ring / sealing washer kit for a little over $ 200 USD . Compressor is suppose to be new . For my Chevy Caprice .
But I live in the USA so your prices may be different ?
I would not buy a compressor from an auto salvage place . What you get may be in worse shape than what you have .
God bless
Wyr
(This post was edited by WyrTwister on Apr 25, 2014, 10:32 PM)
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Discretesignals
Ultimate Carjunky
/ Moderator
Apr 26, 2014, 4:03 AM
Post #8 of 9
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Re: A/C Leak Finding
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I'd be leery of buying cheap compressors off the internet also. They may not cover damage caused by the compressor if it defective. There are a lot of Chinese knock offs running around out there, so be careful.
Since we volunteer our time and knowledge, we ask for you to please follow up when a problem is resolved.
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