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AC comes out hot. 1990 3.0L

Discussion in '2nd Gen 4Runners (1990-1995)' started by rabidvajer, Jun 7, 2021.

  1. Jun 7, 2021 at 9:08 PM
    #1
    rabidvajer

    rabidvajer [OP] New Member

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    Hey 4Runner family

    When I turn on the AC in my 1990 3L 4x4, the air comes out HOT. In Southern California, So I'd like to get this fixed before it gets any hotter. Any suggestions on how I can begin solving this? Thanks!
     
  2. Jun 7, 2021 at 9:41 PM
    #2
    AdmiralNoodle

    AdmiralNoodle New Member

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    Is there any change in the way the airflow sounds switching from hot to cold? If it's coming out hotter than ambient, sounds like the blendoor in your hvac ducting isn't moving properly
     
  3. Jun 8, 2021 at 11:11 AM
    #3
    trlhiker

    trlhiker New Member

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    Either take it in to have it checked out to see what the issue is or try to recharge it yourself but make sure you change the Schrader valves out when you do it.
     
  4. Jun 8, 2021 at 12:16 PM
    #4
    KRUPP

    KRUPP New Member

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    I'm having a similar issue with the AC on my '91 w/3.0. I ordered some R12 replacement refrigerant on Ebay in hopes that solves it. We'll see in a few days.
    Trlhiker: Please expand on your schrader valve replacement comment.
     
  5. Jun 8, 2021 at 12:35 PM
    #5
    AdmiralNoodle

    AdmiralNoodle New Member

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    Personally the store storebought ac recharge kits don't sit well with me, I've had several customers use them and kill their systems. They have stop leak in them usually, which can sometimes clog the components.

    As far as changing the valves, I wouldn't say it's necessary, and if your system has refrigerant in it, you'll have to clear that out before removing the old valve.

    On top of that, you'll fill your system with air, which has to be evacuated before recharging with refrigerant.

    A simple ac service shouldn't cost too much at a local shop, I recommend starting there so they can use the right equipment
     
  6. Jun 8, 2021 at 1:10 PM
    #6
    KRUPP

    KRUPP New Member

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    Thanks Admiral.
    I didn't like the idea of stop leak in there either. My issue is that around here, all the shops I called don't work with/carry R12. So, you're kinda stuck with converting to the newer 134 (I think), or using R12 or the equivalents.
     
  7. Jun 8, 2021 at 2:03 PM
    #7
    AdmiralNoodle

    AdmiralNoodle New Member

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    Yeah I've been there too, when I had my old miata. I switched to 134a, ac worked good enough for a convertible haha
     
  8. Jun 8, 2021 at 2:44 PM
    #8
    rabidvajer

    rabidvajer [OP] New Member

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    so I put the AC on full blast, and shift the tab left and right from cold and hot. I don't notice a change in the sound or airflow.
     
  9. Jun 8, 2021 at 3:52 PM
    #9
    AdmiralNoodle

    AdmiralNoodle New Member

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    And no change in temp when switching?

    One other thing to check, I believe in 90 the trucks still used heater valves to control heat to the cabin. An in line valve on your heater hose under the hood, controlled by a cable/linkage. Make sure that moves with the temp knob on the hvac
     
  10. Jun 8, 2021 at 4:32 PM
    #10
    rabidvajer

    rabidvajer [OP] New Member

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    Yea. No change in temp. Hot hot hot.

    I'll look into the heater valve. Thanks for the suggestion
     
  11. Jun 8, 2021 at 4:49 PM
    #11
    AdmiralNoodle

    AdmiralNoodle New Member

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    Yeah sounds like heater valve or something in the ducting, let me know what you find.

    Good luck!
     
  12. Jun 8, 2021 at 7:32 PM
    #12
    trlhiker

    trlhiker New Member

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    Where you hook up the recharge to each port is called a schrader valve much like on a bicycle tire. The internal piece is what will possibly need to be replaced. It is recommended that when you recharge a system, that internal valve should be replaced.
     
  13. Jun 10, 2021 at 10:05 AM
    #13
    ZARTT

    ZARTT New Member

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    1995 4Runner, Black,Tan Interior, 5spd.,(convert from A340) 207,000 mi., on its 3rd 3VZE.
    Ford Taurus 2 spd. elec. cooling fan, GM CS-144 alternator upgrade. Intimidator AGM battery.
    Hi:

    It is pretty impossible to DIY repair an A/C system legally, and successfully, in any vehicle, without the proper tools.
    You must first determine if then system is even turning on. Start the engine, let it warm up, and turn on the A/C with vents set the way you usually like them.
    Raise the hood and watch the A/C compressor with the engine at idle. You should see the compressor clutch cycle on, and off for a set time period.
    If this is not happening, then the refrigerant quantity is too low for the compressor to activate.
    This is a fail safe feature, so the compressor doesn't destroy itself trying to pump an empty system unlubricated.
    This will also tell you that you most likely don't have a problem with the venting that directs the airflow under the dash.
    If you change out the valves in the low, and high side pressure pipes (as some posters suggest) the system will bleed out what ever refrigerant is in it, and you have just made the job more expensive.
    If the refrigerant is R-12, it is totally illegal to vent this substance to the atmosphere. It must be captured
    I have serviced countless HVAC systems in all types of vehicles going back to Roman chariot days, and have never heard of a situation that required changing the Schrader valves in the ports.
    Have the A/C system checked and serviced by a reputable shop, with the proper tools and equipment for capturing any refrigerant bleed off.
    They will ensure that you have a leak free system that will last for years.
    And best of all you get a guarantee.
    Good Luck
    Art
     
    AdmiralNoodle likes this.
  14. Jun 10, 2021 at 1:21 PM
    #14
    KRUPP

    KRUPP New Member

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    Hey Rabidvajer.

    Received the refrigerant recharge kit today and recharged the system. Was very low on pressure, like around 6-7lb. Added one can to get it to about 31lb. Could have used a bit more, I think. But that meant puncturing another can and only using part of it, even though the guy says the stuff is enviro-friendly.
    Temp in center vent runs at about 39-43d now going down the road. Not arctic-like, but good enough and I don't want to push the old system too much more.
    Think that was an easy fix. We'll see how it holds.
    This is what I used... https://www.ebay.com/itm/122508929925
     
  15. Jun 10, 2021 at 9:56 PM
    #15
    ZARTT

    ZARTT New Member

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    1995 4Runner, Black,Tan Interior, 5spd.,(convert from A340) 207,000 mi., on its 3rd 3VZE.
    Ford Taurus 2 spd. elec. cooling fan, GM CS-144 alternator upgrade. Intimidator AGM battery.
    Hi:

    There are two major reasons not to DIY refill your A/C system with what is sold as R-12, and R-134 compatible refrigerant.

    1.) The substance is a mix of propane, and isobutane, and in the short term can provide as a substitute for either of the original refrigerants.
    BUT, the gas molecule of the substitute is much smaller than the others, and, given enough time, will slowly leak past the O-rings, causing them to deteriorate,and leave the system empty.
    2.) The substance when mixed with oxygen, forms a highly explosive gas, that just needs a point of ignition to cause all kinds of havoc.

    I'm not trying to be a scare monger here, but chemistry is chemistry, and nothing can change that.

    Art.
     

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