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  #16  
Old 07-17-2006, 07:12 PM
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Quote:
Originally Posted by Earthworm
You don't have to pull the dash apart...only the glove compartment.

Are you sure?

As I had to pull the dash in our Legacy...
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  #17  
Old 07-17-2006, 07:17 PM
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I'll chime in here. I asked my son how bad of a job it was going to be, and he told me too, that the dash can stay in, just the glove box assy comes out. It sounds like a tight job to do, but not as bad as others.
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  #18  
Old 07-18-2006, 10:00 AM
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Once you evacuate then disconnect the 2 pipes going through the firewall the entire unit comes out as an assembly. It would be a very good idea to clean it out while it's out. Yucky!
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  #19  
Old 07-18-2006, 08:30 PM
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a/c not working

So, I've replaced the compresser and dryer, repaired a hose, vacuumed the system out and it held for an hour. Put in 2 cans of r134. The compresser cycled repeatedly for short periods. Low pressure was off the gauge (all the way past the top number). I let out pressure a little at a time until the compressor runs consistently. The big line running back toward the fire wall is still warm, but in 96 degree weather it blows cool air. A simple gauge shows the pressure, with the compressor running, as "low", no freon is visible flowing in the site glass of the dryer.
Does this make it a expansion valve problem, a condensor blockage, a weak compressor, all the above? Any advice would be appreciated.
BTW, the a/c hasn't worked for two years, but through persistence I'm up to "cool". Seems it should be "cold".
David
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  #20  
Old 07-19-2006, 10:17 AM
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Roughgem, have you cleaned out the condenser? A lot of times this problem is due to inadequate airflow to cool the R134. It should blow cold enough that it's freezing your hands on the steering wheel
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  #21  
Old 07-19-2006, 08:53 PM
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a.c expansion valve

No I did not. Is it possible to blow compressed air backward through it? Say, from drivers side back toward the passengers side. I've really tried to do most of my own work, but at some point it may be futile. Thanks for your response.
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  #22  
Old 07-19-2006, 09:17 PM
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Quote:
Originally Posted by dannmarr
Beav, if no refrigerant flows through the system because of a faulty expansion valve, wouldn't it cause high pressure on the high side and low pressure on the low side thus triggering the pressure switch and shutting the compressor from damage?
No.

Added/edited for clarification:
Fact of life: you can't blow what you can't suck. Stuck TXV will cause 10-15" vacuum on low side and since there isn't anything available to the compressor to compress the high side will usually only rise about 10-15lbs. above static.

On systems with low pressure cycling switch the compressor may shut down, as the system is cycling off to thwart evaporator freezing. This is normally found on orifice tube based systems. Typically TXV based systems don't worry about too-low pressure, but there are always exceptions. So, as I stated above, a stuck closed TXV can lower pressure to the point a low-pressure switch will open the compressor circuit BUT it is not a normal control device as such and the compressor will continue cycling as pressure equalization repeatedly occurs during the off periods. You may think I'm picking nits but I feel it is important to be clear, especially here, as there seems to be some difficulty in properly diagnosing the problem.

Quote:
Originally Posted by danmarr
Receiver Drier (Filter Drier) - Expansion Valve System
This is the earliest and I think the best system. This system uses an expansion valve to control refrigerant flow and cycles the compressor clutch to control evaporator temperature.
If I wrote that I had a brain fart. Systems with TXVs absolutely do not require, or normally have, means to open the compressor clutch circuit other than at the operator's controls, or protection devices such as a superheat switch and thermal limiter, etc. Compressor cycling as a means of temp control didn't show up until orifice tubes were employed.
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Last edited by Beav; 07-20-2006 at 10:51 AM.
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  #23  
Old 07-28-2006, 06:48 AM
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I remember you mentioned you had high pressure in the low side and low pressure on the high side. I did some research through my AC books and found; the cause of high pressure on the low side is the expansion valve is stuck in the open position. The cause of low pressure on the high side is a defective discharge valve in the compressor. Hope this helps with your problem.
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  #24  
Old 07-28-2006, 01:28 PM
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Well we'll know shortly. Since compressor was replaced with no change, we ordered and recieved one of the last 4 expansion valves in the country from SOA. Son is planning on installing this weekend then take into work to recharge system. Speaking with him just today, if this doesn't fix it...I may just have to learn to not have A.C. in the hot weather. Somtimes you just don't want to give up though!

I will let you all know in this post how it turns out.

Scott

BTW. there is a guy here in Omaha with a Black 1997 SVX he is planning on selling if anyone is interested. I can pass on his email.
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  #25  
Old 07-31-2006, 11:15 AM
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YEA!
A/C finally works blows 47deg. air! the expansion valve fixed the problem. I tell you what, its amazing what crap can find its way to the evaparator case. It was good to get it pulled out and cleaned up as well.

Again, lucky for me to have an "inhouse" Subaru tech to work on such a complicated car.

Scott/Omaha
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  #26  
Old 07-31-2006, 11:28 AM
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huck369 huck369 is offline
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Glad you got it working Scott!

I guess I need to tear into mine now
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  #27  
Old 08-04-2006, 11:40 AM
Roughgem Roughgem is offline
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expansion valve

Well..... I've removed the unit under the dash and cleaned out the core area. I've dismantled the brass assembly which I believe is the expansion valve. After removing the inner nut and spring assembly I'm able to blow air through the body of the brass assembly both ways. Would this constitute an open valve? Or is the ability to blow air through the assembly not right. (My original problem was high pressure on low side with no cooling through the core. The tube running into the dryer would be cold so I assume the restriction at the dryer acted as an expansion valve of sorts.)
Any help would be appreciated.
David
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  #28  
Old 08-04-2006, 06:38 PM
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High pressure on the low side indicates the expansion valve is either stuck open or too much refrigerant is being feed due to a defective expansion valve. Your best bet is to replace it while it's out.
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