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  1. #1
    Join Date
    Oct 2019
    Posts
    1
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    Two evaporators one compressor/condenser

    Didnt really see a section for automotive HVAC or if that is usually discussed here but also didnt see a rule against it so here goes.

    I have a van that has a front and rear AC evaporator. The rear one has a slow leak (can see the dye with IR light).

    My question: It looks as if the AC lines just have a simple 'tee' in them with two more lines going to the rear condenser. Can I theoretically just disconnect the rear evap and cap the lines? I don't use it anyway. It looks to be connected in parallel with the front one, not series.

    Thanks all

  2. #2
    Join Date
    Jan 2010
    Location
    Central Texas
    Posts
    255
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    One option would be to just purchase the lines for a van that didn't have the dual AC option and charge based on the single AC capacity.

  3. #3
    Join Date
    Jun 2003
    Location
    Texas
    Posts
    1,436
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    yes

  4. #4
    Join Date
    Jul 2002
    Location
    Chariton, Iowa
    Posts
    559
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    Yes, you can, but no, you shouldn't. You should fix it right.

    Oh, and I assume you meant UV light not IR.

    Rear A/C block-off kits are readily available, my own van, a 5th gen Grand Caravan, has a block-off kit on it right now and was this way when we got it.

    4th and 5th gen Chrysler vans are known for rear evaporator leaks because the lines and H block expansion valve where it goes up through the floor pan are right behind the passenger rear tire with NO shielding from road salt, dirt, and debris thrown up on them causing physical damage as well as electrolytes for galvanic corrosion.

    Here's why I say don't do it:

    The dual evaporator (front and rear A/C) version isn't just the front only system with a pair of tee fittings, lines, and another evaporator scabbed on, they usually have a larger displacement compressor as well.

    For instance my Dodge is a Denso 10SR17C compressor, but the front only version uses the 10SR15C. The 15 and 17 are the displacement. Probably roughly 150 and 170 cc/rev.

    Similarly for the GM vans in the 2000s models. Mitsubishi scroll compressor MSC105CVS for front only and MSC130CVS for dual. Again 105 VS 130 cc/rev (cubic centimeters per revolution)

    Here's where the trouble starts, just like an oversized house A/C system the now too large compressor short cycles and reduces the comfort because the vent temps are varying more than they should. Yes this is a cycling clutch system so some cycling is inevitable and normal but not like this. It was annoying to say the least.

    I suppose you could swap the compressor and lines to those of the front only version but it would be easier and cheaper to just replace the leaking parts.

    I plan to replace then reconnect the rear evaporator on the Dodge so that it works correctly again. Oh, and add shielding so it stays clean and happy.

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