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99 Saturn SL2 air conditioner

Tiny
MIKE9151406
  • MEMBER
  • 1999 SATURN SL2
  • 4 CYL
  • 2WD
  • MANUAL
  • 180,000 MILES
Hi, compressor short cycling at idle and pressures are Very High.
At idle speed,
Compressor running:
Low side 70 lbs
Hi side 425 lbs

compressor off:
Low side 145 lbs
Hi side 250 lbs

I've had car since new, system has never been serviced before and OD at 180,000 miles
Believe I heard belt squeal (not surprised?) Any suggestions would be greatly appreciated!
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Wednesday, May 11th, 2011 AT 11:42 PM

8 Replies

Tiny
WRENCHTECH
  • MECHANIC
  • 20,761 POSTS
If you haven't added any refrigerant to it, check to verify the cooling fan is working at full speed.
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Thursday, May 12th, 2011 AT 12:12 AM
Tiny
SATURNTECH9
  • MECHANIC
  • 30,869 POSTS
Just to add to this one make sure the radiator fan is running full speed plus make sure there is a lot of air coming out of the fan I have seen radiators and a/c condenser get clogged up with debris sand dirt cat fur plastic bags and not allow enough air flow to be pulled thru causing the a/c to cycle overheat etc.
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Thursday, May 12th, 2011 AT 7:07 AM
Tiny
MIKE9151406
  • MEMBER
  • 4 POSTS
Hi again,
Thank you for the replies. I looked at the condenser & radiator and a bit dirty but not bad. Also fan is running. I might add the pressures high when the car is first started (first time I checked pressures the ambient temp was in the mid 60's, I had just started the car and engine had not warmed up yet).
I had looked for info on the web for stuck expansion valve etc but couldn't find any answers to high pressure on suction and pressure lines.
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Thursday, May 12th, 2011 AT 12:28 PM
Tiny
WRENCHTECH
  • MECHANIC
  • 20,761 POSTS
You might want to try a different set of gauges because a lot of what your saying just doesn't add up. First off, the static (engine off) pressures should be equal and should generally correspond to outside temperatures. The other thing is for both sides to read that high, either someone has overcharged the system, used the wrong refrigerant or the condenser and/or condenser fan are just not doing their job which you say the fan is working so I would try different gauges. That's definitely not an expansion valve causing pressures like that.
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Thursday, May 12th, 2011 AT 12:46 PM
Tiny
MIKE9151406
  • MEMBER
  • 4 POSTS
I hadn't checked static pressures yet (engine off) but will. The pressures I showed were with engine running but compressor cycling on & off -maybe 5 to 10 seconds on and 5 to 10 seconds off and those were the pressures when compressor switched on & off. I will try other gauges. These were my son's and My old gauges are for R12 but his hoses may fit my gauges.
I know the readings make little sense but after hearing the belt (or clutch) squeal I thought something was really wrong. I've had the car since new and this is the first problem with the AC. System has never had a component changed or freon added. It does cool when driving but yesterday I could really tell when the compressor kicked on (loaded engine more than usual). I really appreciate your help with this and will do more testing.
Thanks again!
Mike
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Thursday, May 12th, 2011 AT 1:46 PM
Tiny
WRENCHTECH
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The pressures would make sense of it was overcharged or the fan wasn't working or the condenser is not condensing for some reason. Try getting a water hose while the gauges are attached and the system is running and spray the condenser and see what the pressures do.
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Thursday, May 12th, 2011 AT 2:04 PM
Tiny
MIKE9151406
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R134A hoses didn't fit my old guages but my son in law has newer R134 gauges and I'll try his tonight after he gets home. Water on the condenser is a great idea and I'll try it at the same time. None of this makes sense to me right now either and I'm the only person who has even raised the hood.
Over charge would make sense but it's never had anything added.
Thanks again for the help and the very quick reply's!
I will reply with more info after more checks tonight.
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Thursday, May 12th, 2011 AT 2:24 PM
Tiny
WRENCHTECH
  • MECHANIC
  • 20,761 POSTS
Closing question
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Thursday, June 30th, 2011 AT 11:29 PM

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