The Subaru SVX World Network   SVX Network Forums
Live Chat!
SVX or Subaru Links
Old Lockers
Photo Post
How-To Documents
Message Archive
SVX Shop Search
IRC users:

Go Back   The Subaru SVX World Network > SVX Main Forums > Technical Q & A

Reply
 
Thread Tools Display Modes
  #16  
Old 07-12-2005, 06:15 PM
Earthworm's Avatar
Earthworm Earthworm is offline
Meow!
 
Join Date: Mar 2002
Location: Winnipeg, Manitoba
Posts: 11,957
Send a message via ICQ to Earthworm Send a message via AIM to Earthworm Send a message via MSN to Earthworm Send a message via Yahoo to Earthworm Send a message via Skype™ to Earthworm
I don't know the exact pressures and yes they will be different for different cars. At what pressures does the compresser stop turning for you?
Reply With Quote
  #17  
Old 07-12-2005, 06:59 PM
Beav's Avatar
Beav Beav is offline
Not as old as Randy
 
Join Date: Nov 2001
Location: Louisville, KY
Posts: 3,883
Significant Technical Input
Normally one assumes that R-12 will yield 1 degree per 1 psi on the low side. R-134 is close enough to consider the same. Soooo..... most systems will operate best at approx 31-34 psi on the low side when full and spinning at ~2,000 rpm. Give it a few minutes to somewhat cool the interior as elevated interior temps will affect the reading. Lower pressures will usually result in compressor clutch cycling due to low refrigerant charge levels.

Watch the sight glass, if the interior is below ~80 degrees, the low pressure is 30-35 psi and you still show bubbles (other than a few random ones) you may have air/moisture in the system which will require an evacuate and recharge. Evacuating not only means draining the refrigerant but also placing the system under deep vacuum for a period of time in order to cause air and moisture to boil, in order to be evacuated.

R-134 is very prone to poor cooling due to incorrect charge levels. A few ounces one way or the other will cause poor performance. Also those that succumb to Moore's Law will eventually learn that over-charging the oil in the system will cause various maladies, including the fact that the more oil in the system leaves that much less room for refrigerant.

Same goes for those that think installing leak sealer is a good idea. It works by sealing when it comes into contact with air. Hmmm... now if they had a system leak and didn't evacuate the system properly before installing the sealer, the system will be full of air... Next, after finding it doesn't work at all, they take it to a repair shop. They are too embarassed to tell anyone that they tried to fix it and couldn't. So, here goes the tech with his $4000 a/c recycler and (especially if it's R-12) expensive cylinder of refrigerant. First move, hook up and check pressures, allowing uncured sealer into his machine. Then a quick evac and recharge and he has a contaminated cylinder of refrigerant. Nice. Now the customer is responsible for maybe $2000 or more in damage to his own car plus another $4000 - $5000 to the repair shop's equipment. I just had to throw this in because I've seen it happen to many shops when I was selling tools. It's never pretty.
__________________
ASE Certified Master Automotive Technician w/L1.
ASE Certified Master Medium/Heavy Truck Technician.
Certified EVT (Emergency Vehicle Technician)
Reply With Quote
  #18  
Old 07-12-2005, 07:05 PM
kuoh kuoh is offline
Registered User
 
Join Date: Mar 2002
Location: Kansas City, MO
Posts: 1,200
Send a message via AIM to kuoh
Honestly, I haven't made note of the exact cut-in/out pressures, as I've checked it in various states between cold and hot, but it's between green and yellow with 25 PSI as the differentiation point.

KuoH

Quote:
Originally Posted by Earthworm
I don't know the exact pressures and yes they will be different for different cars. At what pressures does the compresser stop turning for you?
Reply With Quote
  #19  
Old 07-12-2005, 07:24 PM
kuoh kuoh is offline
Registered User
 
Join Date: Mar 2002
Location: Kansas City, MO
Posts: 1,200
Send a message via AIM to kuoh
Thanks for the insight Beav. The replacement drier I purchased does not have a sight glass, so unfortunately I cannot check for it that way. I did have it evacuated, but there may be a bit of moisture still in the system as they didn't put under a deep vacuum. It may also be that there is too much oil, as I didn't drain any oil out of the system before adding the R134. I haven't added any sealer, as the shop told me that it held a vacuum just fine.

It seems to cycle more in warm rather than hot weather, but I haven't really made any close observations. I haven't been driving much lately, but it has worked for the most part.

KuoH

Quote:
Originally Posted by Beav
Normally one assumes that R-12 will yield 1 degree per 1 psi on the low side. R-134 is close enough to consider the same. Soooo..... most systems will operate best at approx 31-34 psi on the low side when full and spinning at ~2,000 rpm. Give it a few minutes to somewhat cool the interior as elevated interior temps will affect the reading. Lower pressures will usually result in compressor clutch cycling due to low refrigerant charge levels.
Reply With Quote
  #20  
Old 07-13-2005, 07:46 PM
JonathanS JonathanS is offline
Registered User
 
Join Date: Apr 2005
Location: Potomac, MD
Posts: 28
Do your own diagnostic

When my a/c was leaking I invested $35 for fluorescent light and goofy yellow glasses, plus $5 ($8?) for Interdynamics dye, plus another $20-25 for an Interdynamics a/c recharger w/gauge.

After charging and dying via the low-pressure port, I spent a couple of sessions looking over the whole a/c system before I finally found the slow leak. It was small and well-hidden, especially because the leak was soaking into the foam on the passenger side of the radiator.

When I brought it into to the dealer (my first-time at the dealer with my new-to-me SVX), I explained to the "receptionist" (whatever you call those guys who write up your order) exactly where the leak was, showing him a picture of the part from subaruparts.com. He said their mechanics would need to do their own diagnosis, blah, blah, blah. Once they did, however, they concurred with my findings and replaced the part, the pipe running vertically along the passenger side of the of the radiator. The dealer charged $277, parts and labor, but I paid only $100 because of my extended warranty. (Plus my diagnostic costs.) I felt like I came out ahead because I KNEW where the problem was and therefore felt in control of the transaction.

Good luck!
Reply With Quote
  #21  
Old 07-13-2005, 10:58 PM
Ron Mummert Ron Mummert is offline
Invisible avatar
Alcyone Gold Contributor
 
Join Date: Apr 2001
Location: Shawsville, VA (Formally Ellicott City, MD)
Posts: 3,797
Send a message via AIM to Ron Mummert Send a message via Yahoo to Ron Mummert
Can anyone (Beav) tell me why my '92 with 138K still has a flawlessly performing R12 A/C system? (kiss of death). I don't know if anything was ever monkeyed with by prior owners, but in the last 4 plus years & 50K, I ain't done nothin' but pray to the freon Gods every May, & it seems to work. I can live with roaring bearings, & oil puddles, but no A/C in mid-Atlantic humidity would make me consider trading the beast even-up for a '92 Taurus if the cold stuff works. The car's garaged, & seldom abused (Hmmmm...) - any direct relationship, or is my luck about to go south?

Ron.
__________________
Good s**t happened. 69 was worth the wait.

'92 stock semi-pristine ebony - 160K
'96 Grand Caravan - 240K
'01 Miata SE - 79K
'07 Chrysler Pacifica - 60k - future money pit.
Reply With Quote
  #22  
Old 07-14-2005, 10:46 AM
Yoda3000's Avatar
Yoda3000 Yoda3000 is offline
(This account is in rememberance of)Duct Tape Man
 
Join Date: Dec 2002
Location: Socorro, NM
Posts: 250
Send a message via AIM to Yoda3000
so... just because the compressor doesn't click on or spin when the A/C is on ... Does that mean the compressor is bad or something else? Also, where can I get a $200 reman unit?

Thanks
--Mike
__________________

Early deceased SVXWN Member
July 1986 -- February 2007

Michael - Duct Tape Man

1992 Burgundy SVX LS-L, 138K: Brembo Slotted/Drilled Rotors, B&M Tranny Cooler and Filter, SmallCar Shift Kit

1992 Burgundy SVX LS-L, 123K: DEAD FROM FATAL HAIL DAMAGE, Parting out so PM me if you need something.

"It's only after we've lost everything that we're free to do anything" - Fight Club
"This is not my life, this is not my home, this is not me. I HATE THIS!" - Static X
Reply With Quote
  #23  
Old 07-14-2005, 11:16 AM
Earthworm's Avatar
Earthworm Earthworm is offline
Meow!
 
Join Date: Mar 2002
Location: Winnipeg, Manitoba
Posts: 11,957
Send a message via ICQ to Earthworm Send a message via AIM to Earthworm Send a message via MSN to Earthworm Send a message via Yahoo to Earthworm Send a message via Skype™ to Earthworm
No, usually it's pressure related.
Reply With Quote
Reply

Thread Tools
Display Modes

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off

Forum Jump


All times are GMT -6. The time now is 01:05 PM.


Powered by vBulletin® Version 3.8.7
Copyright ©2000 - 2024, vBulletin Solutions, Inc.
© 2001-2015 SVX World Network
(208)-906-1122