Civic A/C help. Is this mechanic full of chit?

Discussion in 'OT Driven' started by parabola, Sep 19, 2006.

  1. parabola

    parabola New Member

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    I bought a 94 civic from a friend about a year ago. It had been sitting for 6 months but friend said the "a/c system was replaced" about a year before that.

    When I got it, the A/C would blow but not cold. I figured it had a leak so I took it to a mechanic which confirmed the leak, fixed it, and recharged it. Since then it blows cooler, but not cold, and takes forever to get cool in the first place. It can take 15 minutes to get it to blow 70 degrees if it is in the 90s outside. The coldest it will blow is about 65 or so and that is only when moving at highway speeds.

    I took it back to the mechanic and he checked it over for leaks and said there were none. After more diagnosis he said the only thing he can figure is that the compressor was "weak" and couldn't build up the appropriate pressures. He didn't charge me for the 2nd diagnosis, but wanted ~$400 for a new compressor.

    I've never heard of a "weak" compressor and due to the fact that it only couple years old, I am finding this hard to believe.

    Any ideas? Is this diagnosis plausible?
     
  2. Subie Driver

    Subie Driver Eye see what you did there.

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    Sure, sounds plausible. First, how sure are you that the compressor was replaced a couple years ago? And if it was replaced, was it replaced with a new, rebuilt, or used compressor? But if it's blowing cold(er) air, then there isn't a leak; if the re was a leak, there would be no more refrigerant, and it would be like it was before. But a bad compressor will do like the mechanic said, and without proper pressure, it won't cool right, because presure is the key to refigerants.
     
  3. deusexaethera

    deusexaethera OT Supporter

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    Indeed. However, a slight underpressure will cause air conditioners to run colder on the cold side, which feels nice at first, so you won't really notice. Later on, if coolant keeps leaking (as opposed to simply being underfilled by the mechanic), the cold side will start growing ice, at which point it won't be able to absorb heat well enough, and then the hot side won't have enough heat to dissipate, and the system breaks down. Modern A/C compressors turn themselves off just before this happens, but as I said, a slight underpressure will actually make the A/C feel like it's working really well.
     
  4. parabola

    parabola New Member

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    Well, the original work was done by the Honda dealer (friend is kind of a sucker :p). The compressor and associated wiring all look new compared to everything else. I supposed they could have put in a rebuilt but I'd like to imagine the dealership wouldn't do such a thing.

    Hrm, well if a compressor failing in this manner is plausible than, well, that sucks. :p

    I didn't pay much for the car and just wanted to use it as transport to/from work but I really need A/C. I just didn't want to spend that sort of cash on this vehicle.
     
  5. deusexaethera

    deusexaethera OT Supporter

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    Yeah, fog is just humid air that's been cooled off a little.

    I assume you can overcharge the system, yes, but it's better to let a pro service that system. A/C can cost thousands to repair if you burn out the compressor or blow a hose.

    Next time the A/C gets too cold, turn up the heat a little but leave the A/C on. That turns the system into a dehumidifier, which will actually work better to keep you cool than colder air will.
     
  6. deusexaethera

    deusexaethera OT Supporter

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    Yeah, my old Mazda used to have an economode on its A/C; all it requires is two thermostats set to trigger at different temperatures and a switch to change which one controls the compressor at any given time. I wish my Passat had that feature, esp. with it's cute little 1.8t engine.
     

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