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308 air cond. problem

Discussion in 'Technical Q&A' started by shifty308, Aug 18, 2004.

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  1. shifty308

    shifty308 Karting

    Aug 7, 2004
    75
    coulterville ca
    Full Name:
    steven schiffler
    #1 shifty308, Aug 18, 2004
    anyone out there have this problem, sometimes my air cond. wont turn on, but when it does work it gets good and cold. i cant detect a pattern to the prob. turning it on and off repeatedly doesnt help sometimes i leave the switch on when its not working and viloa! it comes on, it may stay on for hours or minutes but it always goes back off, usually when its hottest. i live in sierra nevedas in cal. so it gets hot, windows down are cool when im moving (hear the engine mo betta) but when i have to slow down it sucks, any ideas? thanx in advance for any advice y'all.
     
  2. Jdubbya

    Jdubbya The $10 Trillion Man
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    #2 Jdubbya, Aug 18, 2004
    Does the fan come on all the time and it just doesn't get cold, or is it that the fan doesn't blow at all sometimes? If the fan blows all the time but it's just not cold I would say compressor problems possibly just the clutch. However if it's the blower it could be as simple as bad contacts in the switch or on the fuse panel.

    Need more info to properly guess at it!
     
  3. shifty308

    shifty308 Karting

    Aug 7, 2004
    75
    coulterville ca
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    steven schiffler
    #3 shifty308, Aug 18, 2004
    thanx jdubbya, well the fan blows but the compressor goes in and out, i was wondering if it could be the rotary sw. for comp volume but now that u mention it the clutch would make more sense, any idea how big a job ? thanx again
     
  4. Jdubbya

    Jdubbya The $10 Trillion Man
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    #4 Jdubbya, Aug 19, 2004
    Try a search here. I'm sure there are plenty of threads about AC compressors. I've got to dig into mine one of these days too, but too many other things to do right now. I've heard that you can replace them with a more standard rotary one easier than trying to fix the piston one??
     
  5. WaltP

    WaltP Formula 3

    Nov 1, 2003
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    #5 WaltP, Aug 19, 2004
    A low freon charge may be causing your problem. You really need to but a set of gauges on it.
     
  6. shifty308

    shifty308 Karting

    Aug 7, 2004
    75
    coulterville ca
    Full Name:
    steven schiffler
    #6 shifty308, Aug 19, 2004
    dont think its freon related it gets ice cold when it works, and sometimes works all day. i feel it must be either clutch or electrical, which i guess woud include the clutch, oh well wont need it till spring soon.
     
  7. Steve Magnusson

    Steve Magnusson Two Time F1 World Champ
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    Jan 11, 2001
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    #7 Steve Magnusson, Aug 19, 2004
    shifty -- If you have access to a multimeter try measuring the DC voltage between the single wire going to the AC compressor clutch and ground (you can even unplug the wire to make the measurement more easily -- of course, the AC won't really work when unplugged):

    1. If you turn the AC "on" and this wire doesn't go +12V then you've got something wrong electrically upstream (bad high/low pressure switches at the dryer, +12V input power missing, low freon charge just on the cusp of working the low pressure switch, etc.)

    2. If you turn the AC "on" and the wire does go +12V (relative to ground), but when you plug it back into the clutch the AC still doesn't come on then that's a bad sign for the clutch itself.

    Anyway, just thought I'd suggest this as an easy-ish first test (most tests on a F aren't ;))

    Please also give year/model/version 308.
     
  8. Verell

    Verell F1 Veteran
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    May 5, 2001
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    #8 Verell, Aug 19, 2004
    Definitely can be a low freon problem. If the charge is marginal, then on cooler days the pressure won't be high enough to actuate the low pressure switch. This will keep the clutch from being powered.

    Another 5-7 degrees can raise the pressure enough to trip the switch. Once the switch is tripped, pressure has to go quite a bit below the turn-on pressure before the switch will drop out.

    A system with low refrigerant can actually run colder than one with the normal charge. It won't be running as efficiently, and the evaporator coil can actually frost up because it's too cold! Then the freeze-up detector will cut power to the clutch to let the evaporator coil warm up. The compressor won't run until the evaporator defrosts.

    This interactive cycle may explain your symptoms.

    I've deliberately run a R134a converted system a couple of oz low on refrigerant to get it to blow extra cold.

    BTW, you don't need a voltmeter to test clutch power, just a 12V test light probe. When the bulb lights, the clutch has power.
     

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