Automotive Air Conditioning Information Forum (Archives)

labans on Tue August 31, 2010 2:38 PM

Year: 1992
Make: Toyota
Model: Previa
Engine Size: 2.4
Refrigerant Type: r-12
Ambient Temp: 96
Pressure Low: -20
Pressure High: 55
Country of Origin: United States

Hi:
I am stumped on this problem. This is a traditional r-12 system with a block-type expansion valve. I have installed a new Nippon Denso compressor, new Toyota expansion block and new Denso drier.
I checked the system when it was open and could not find any blockages.
However, when I put in about .5 lbs of freon, the suction side goes to -20 and the high side stays at about 55 and the line coming out of the drier immediately starts to sweat and then heads towards
freezing. When I follow that line up to the expansion block, it is freezing cold the entire distance up to where it disappears into the evaporator box.
The high side coming out of the compressor is very hot right up to the condenser. Coming out of the condenser the line is warm going into the drier. The drier itself also begins to get very very cold.
Any ideas?
Thank you,
Labans

bohica2xo on Tue August 31, 2010 2:58 PM

Here's an idea - put the whole 35 ounces of refrigerant into the system before you try to diagnose it.

Does this vehicle have rear A/C?

B.

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"Among the many misdeeds of the British rule in India, history will look upon the act of depriving a whole nation of arms, as the blackest."
~ Mahatma Gandhi, Gandhi, An Autobiography, M. K. Gandhi, page 446.

HVargas on Tue August 31, 2010 5:30 PM

You cannot even begin to diagnose the system until you have the proper amount of refrigerant in the system to check your operating pressures. The line to the condenser should be hot, the line from the evaporator to compressor should be cold.

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labans on Tue August 31, 2010 7:50 PM

Thanks for the help, guys. Turns out that the drier was clogged. New drier--problem fixed.
Labans

HVargas on Tue August 31, 2010 7:55 PM

What exactly was the drier "clogged" with? Driers don't usually clog unless they are filled with debris or sealer.

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iceman2555 on Tue August 31, 2010 10:46 PM

It is possible to 'clog' a drier with too much lubricant. With the recharge rate posted, there is simply not enough refrigerant movement to purge the drier. Wonder what the result would have been if the system had been fully charged?
To properly diagnosis a system performance issue....all variables need to be removed....#1 is a known fully charged system.

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The strongest reason for the people to retain the right to keep and bear arms is, as a last resort, to protect themselves against tyranny in government.
Thomas Jefferson

bohica2xo on Wed September 01, 2010 12:45 AM

Must have been one of Icemann's substandard dryers. With an 8 ounce charge you can return them all day long, just like his compressors...




(Sorry man, I could not resist)



While it is possible to get a defective dryer (restricted) out of the box, it is unlikely. A perfectly good dryer is capable of acting as an expansion device with that small of a charge.

At least the new Denso compressor got a nice break in, with 8 ounces of refrigerant on board & a hot discharge line to help everything settle in without all of that lubricant getting in the way.

B.

-------------------------
"Among the many misdeeds of the British rule in India, history will look upon the act of depriving a whole nation of arms, as the blackest."
~ Mahatma Gandhi, Gandhi, An Autobiography, M. K. Gandhi, page 446.

iceman2555 on Wed September 01, 2010 8:35 AM

Thanks, understand. However, 'my' substandard driers as well as 99.99999999999% of all the others are probably made by political 'detainees' in some far away country of a very large land mass, with extremely large walls around partial borders.
'Nuff said'
Ya'll have fun out there today.
Gotta go to a shop this AM....installer is having a 'severe' clutch issue. Has installed numerous compressors and they all 'short' out or blow the fuse. Of course, this is the #1 shop for this jobber, has been in the business for a thousand years and being doing AC repair for at least 30 years or more....had the rep send some photos....the clutch is toasted....drive is almost melted.....shorted and burned...don't think so....burned and shorted....probably......damn...where did the ability to diagnosis a system problem go....."hey...send me 'other of those compressor's.....this one is defective.....yep, I know the last one was defective also...but heck...gotta get a good one one day......"
The real kicker...this is the reason the compressor was replaced in the beginning.....should have stayed in dental school. Be retired today...or at least working in an office with lots of very young, very beautiful lady assistants.....but then would probably be spending all my income on 'alimony'....can't win.....just can't win.......

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The strongest reason for the people to retain the right to keep and bear arms is, as a last resort, to protect themselves against tyranny in government.
Thomas Jefferson