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Flushing the evap

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    Flushing the evap

    2004 Mazda 3 R134a system wouldn't cool. Gauges show low side going into vacuum. Obvious txv plugged. Suspected grenaded compressor so examined a little oil from the system and it's dark. No particles but that doesn't give me any hope.

    Will replace all major components: comp, cond, dryer, valve, and flush all lines and evap.

    My question is about flushing the evap. It uses a block type txv which bolts to the evap deep in the dash. How do you flush it? Can't flush with txv installed (which would give convenient lines under the hood to connect flush equipment). Without txv connected, there are just 2 holes in the air box that lead to the evap (see link, below).

    How do I flush the evap without contaminating the whole passenger compartment?

    Thanks for your help.

    Last edited by iXod; 07-11-2019, 01:17 AM.

    Assuming that flushing the evaporator with solvent is a good idea, with the expansion valve removed couldn't you flush the low side (exit side) of the evap with solvent and blow that out the inlet pipe?? Like with aerosol AC flush, like from O'Reilly? Wouldn't the old expansion valve catch any particles that made it through the drier?

    I know on my 1988 Mazda truck that if I wanted to flush evap I'd have to remove the evap from under the dash to get the expansion vale off.


    • iXod
      iXod commented
      Editing a comment
      Look at the diagram:

      Removing the valve exposes both ports on the evap. Blow anything into either port, it comes right back out at you from the other port. A real mess. Unless i remove the whole evap...

    Be creative. Direct the "expectorant" out the other and capture it. Use air only some oil will still come out do that back and forth. Can't help it some items are just in horrible locations to deal with,
    MetroWest, Boston