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  1. #1
    1000+ Posts pgti6's Avatar
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    Default One for the A/C Experts

    I need help in working out why my air con has recently begun operating only moderately cold. It's not French, or even European but it's what's known in V8 Supercars circles as the 'Blue' cars.

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    I've checked the fuses (OK), electrical connectors at the TX valve & done a 'spit' test on the High/Low gassing points where the Shrader valves are. No leaks there either. The earth point from the compressor to the block is greasy from a leaking & recently replaced headgasket which I haven't yet cleaned up and checked. Not sure if that would have an effect on it's mediocre performance though.

    I don't want to waste $$$ getting it re-gassed until the problem can be identified & rectified.

    Any suggestions or advice as to where to check next welcomed.

    Thanks.
    405 Mi16 2.2 litre race car for sale.
    http://www.aussiefrogs.com/forum/car...-car-sale.html
    https://www.my105.com/ListingDetails...d/518/id/22164


    Lap times- Sandown 1 27.9
    Phillip Island 1 53.8

    Previous Frenchies-
    1988 205 Gti
    1998 306 GTi6
    1997 306 N5 sedan
    1996 306 N3 XT hatch
    1976 Renault R16TS manual in Avocado
    1976 Renault R16TS manual in Trak Yellow
    1975 Renault 5 Guernsey, Channel Islands
    1972 Renault 4 Guernsey, Channel Islands

  2. #2
    1000+ Posts robmac's Avatar
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    Default

    I don't claim to be an expert.

    If the compressor clutch is "pulling in" and their are no untoward noises from the compressor I'd say the refrigeration circuit is probably OK.

    Have you done the "feel" on the lines with the compressor running. The large line on the evap should be very cold and the hot gas line to the condensor should be very hot (careful).

    Having said that , it's possible for slow leak to deplete refrigerant and leave enough to pass the "spit" test. Without a set gauges you won't know.

    Assuming the refrigeration circuit Ok. Blend door/ motors jammed are a likely fault as is fresh air doors not closing.

    If it is GMH it may be a orifice tube / flooded accumulator system and not TX valve system. Does it have a large aluminium canister plumbed in just before the evaporator?

    Oil soaking the compressor may make the clutch slip but you would expect to hear that.
    Last edited by robmac; 22nd February 2013 at 04:24 PM.

  3. #3
    1000+ Posts pgti6's Avatar
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    Default

    Thanks for the advice Robmac. Expert or not, you've given me some leads to work on.

    The compressor is clutching in & out & the main line (Low) from it is cold. The other line (High) is hot.

    The car isn't a GM vehicle but the other large rwd Aussie passenger car! It does have a TX valve mounted in the engine bay from where it exits into the cabin. Difficult to see where the evaporator is (I imagine it's in the cabin under the dash somewhere).

    It's possible one or some of the flap doors aren't closing, as this was a well known problem with this model where it would break the flap door plastic shaft. To fix that it's a dash out job.

    If I put the air con onto recirculate & the temp drops to a comfortable level, would that help to prove the blend door/motor being faulty?
    405 Mi16 2.2 litre race car for sale.
    http://www.aussiefrogs.com/forum/car...-car-sale.html
    https://www.my105.com/ListingDetails...d/518/id/22164


    Lap times- Sandown 1 27.9
    Phillip Island 1 53.8

    Previous Frenchies-
    1988 205 Gti
    1998 306 GTi6
    1997 306 N5 sedan
    1996 306 N3 XT hatch
    1976 Renault R16TS manual in Avocado
    1976 Renault R16TS manual in Trak Yellow
    1975 Renault 5 Guernsey, Channel Islands
    1972 Renault 4 Guernsey, Channel Islands

  4. #4
    1000+ Posts robmac's Avatar
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    Default

    You need one of these:
    http://speedyairspares.com.au/catalo...Taps-13-1.html

    Cut off the hot water feed to the core in summer.

    Better than pulling the dash out.

  5. #5
    1000+ Posts pgti6's Avatar
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    I have one of those in the shed- http://speedyairspares.com.au/produc..._NL-66-13.html

    Shouldn't be too hard to plumb in.

    Thanks.
    405 Mi16 2.2 litre race car for sale.
    http://www.aussiefrogs.com/forum/car...-car-sale.html
    https://www.my105.com/ListingDetails...d/518/id/22164


    Lap times- Sandown 1 27.9
    Phillip Island 1 53.8

    Previous Frenchies-
    1988 205 Gti
    1998 306 GTi6
    1997 306 N5 sedan
    1996 306 N3 XT hatch
    1976 Renault R16TS manual in Avocado
    1976 Renault R16TS manual in Trak Yellow
    1975 Renault 5 Guernsey, Channel Islands
    1972 Renault 4 Guernsey, Channel Islands

  6. #6
    1000+ Posts robmac's Avatar
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    My mate had a system with Ford E* dashes most people quoted 1 day to dash out /in.

    The trick is leave everything connected and drop the dash onto the front seats (moved right forward). Then work from behind dash under the screen.

    Evaporators were a real problem on these models. He could do the job in 2 hours. He learnt the technique from a ford dealer technician.

    You need two sets hands to R & R for a few minutes.



    I

  7. #7
    1000+ Posts pgti6's Avatar
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    Having done one dash out job on the GTi6 for a heater core replacement, I'm not in a hurry to do another-especially if I need to grow another pair of hands!
    405 Mi16 2.2 litre race car for sale.
    http://www.aussiefrogs.com/forum/car...-car-sale.html
    https://www.my105.com/ListingDetails...d/518/id/22164


    Lap times- Sandown 1 27.9
    Phillip Island 1 53.8

    Previous Frenchies-
    1988 205 Gti
    1998 306 GTi6
    1997 306 N5 sedan
    1996 306 N3 XT hatch
    1976 Renault R16TS manual in Avocado
    1976 Renault R16TS manual in Trak Yellow
    1975 Renault 5 Guernsey, Channel Islands
    1972 Renault 4 Guernsey, Channel Islands

  8. #8
    1000+ Posts pgti6's Avatar
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    May 2001
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    Good news! The culprit was the vacuum line to the heater tap had come off. It would have happened when I was removing bolts during the headgasket job.

    Gotta love these simple fixes!
    405 Mi16 2.2 litre race car for sale.
    http://www.aussiefrogs.com/forum/car...-car-sale.html
    https://www.my105.com/ListingDetails...d/518/id/22164


    Lap times- Sandown 1 27.9
    Phillip Island 1 53.8

    Previous Frenchies-
    1988 205 Gti
    1998 306 GTi6
    1997 306 N5 sedan
    1996 306 N3 XT hatch
    1976 Renault R16TS manual in Avocado
    1976 Renault R16TS manual in Trak Yellow
    1975 Renault 5 Guernsey, Channel Islands
    1972 Renault 4 Guernsey, Channel Islands

  9. #9
    1000+ Posts Fordman's Avatar
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    May 2004
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    Quote Originally Posted by pgti6 View Post
    Good news! The culprit was the vacuum line to the heater tap had come off. It would have happened when I was removing bolts during the headgasket job.

    Gotta love these simple fixes!
    Ah, good. I'll keep that one in mind.

    Cheers.
    2004 Scenic I 2.0 auto (Hers)
    2016 Ford Territory (His)
    2004 WRX (Sunday car)

  10. #10
    1000+ Posts Wildebeest's Avatar
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    pgt16,
    Many years ago I bought an AC test and re-charge kit from K Mart. It contained a temp gauge and a pressure gauge, this was like a tyre pressure gauge with coloured graduations with green, yellow and red. Green being OK, down to red Piss Poor, no gas. The kit included also two canisters for re-charging the system

    This AC kit didn't remain on the shelves for long, I wonder why? I did find use for the temp gauge [in my fridge] and the pressure gauge to impress my friends.

  11. #11
    1000+ Posts robmac's Avatar
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    Quote Originally Posted by Wildebeest View Post
    pgt16,
    Many years ago I bought an AC test and re-charge kit from K Mart. It contained a temp gauge and a pressure gauge, this was like a tyre pressure gauge with coloured graduations with green, yellow and red. Green being OK, down to red Piss Poor, no gas. The kit included also two canisters for re-charging the system

    This AC kit didn't remain on the shelves for long, I wonder why? I did find use for the temp gauge [in my fridge] and the pressure gauge to impress my friends.
    Most basic diagnosis on aircon systems can be done by the "touch" test. IE feeling the pipes and guessing the temperatures. I use three criteria hot, bitingly cold, warm. There are in between of course but correct operation is covered in three temps.

    The above also applies to split system aircons, but frost line on the pipes is also considered when diagnosing them.

    In most cases you can take an educated guess what is wrong before hooking up gauges.

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