Car airconditioner problem

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  #1  
Old 10-01-09, 06:34 PM
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Car airconditioner problem

MY air condtion gets cold some of the time but not others. At times it will be cool and them a humid smell starts just before it gets warm. I have put the coolant in there before but nothing changed. At times it goes out and will start back up, but that is rare.
 
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  #2  
Old 10-01-09, 07:59 PM
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what are we working on /make modle-what type a/c does it have?
any previous diagnostics/repairs?
 
  #3  
Old 10-02-09, 06:56 AM
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1998 Toyota 4 Runner. Never been worked on that I know of.
 
  #4  
Old 10-02-09, 07:21 AM
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i am not a toyota guy.
but it sounds like the evaporator could be freezing over.
thus-the humid smell / then warm
'might' be a thermal switch on the evap.
might be low on freon.
 
  #5  
Old 10-02-09, 12:08 PM
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All of the automotive HVAC compartments I've seen (admittedly only a few) have all of the air blowing through the evaporator (regardless of the desired temperature) and the there is a blend door that directs air over the heat exchanger if heat is called for.

I would think that if the evaporator is freezing over that the air volume through the vents would be reduced significantly. Is this the case here?

Is the compressor cycling on & off frequently with the A/C on or does it mostly stay on?

I don't know if these have TXVs or fixed orifices (probably the latter) or where they are, but if the orifice is BEFORE the evaporator (as they commonly are), check the temperature of the high and low side lines right where they connect to the evaporator (usually on the passenger side of the car near the firewall). They should both feel cold.

I'd put my money on a slightly low refrigerant charge causing the A/C compressor to cycle on and off.

- Joe
 
  #6  
Old 10-08-09, 07:15 AM
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Originally Posted by joec2000 View Post
All of the automotive HVAC compartments I've seen (admittedly only a few) have all of the air blowing through the evaporator (regardless of the desired temperature) and the there is a blend door that directs air over the heat exchanger if heat is called for.

I would think that if the evaporator is freezing over that the air volume through the vents would be reduced significantly. Is this the case here?

Is the compressor cycling on & off frequently with the A/C on or does it mostly stay on?

I don't know if these have TXVs or fixed orifices (probably the latter) or where they are, but if the orifice is BEFORE the evaporator (as they commonly are), check the temperature of the high and low side lines right where they connect to the evaporator (usually on the passenger side of the car near the firewall). They should both feel cold.

I'd put my money on a slightly low refrigerant charge causing the A/C compressor to cycle on and off.

- Joe
I have tried refrigerant. It appears to go out soon after a humid feel and smeel starts.
 
  #7  
Old 10-08-09, 08:06 AM
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How much refrigerant did you put in? Too much is just as bad (if not worse) than too little. The total system charge in ounces should be printed under the hood somewhere.

Is the compressor cycling on & off frequently with the A/C on or does it mostly stay on?

- Joe
 
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