Evaporator / TXV need for a cap? | FerrariChat
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Evaporator / TXV need for a cap?

Discussion in '308/328' started by mixedgas, Jul 30, 2025 at 9:27 AM.

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  1. mixedgas

    mixedgas Formula Junior
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    #1 mixedgas, Jul 30, 2025 at 9:27 AM
    Hi there, 85 GTS euro (if relevant) - I'm installing the Classic Auto Air AC kit and noticed the new thermal expansion valve (TXV) doesnt have the second small 'fitting' that would attach to the evaporator. What are you guys doing to mitigate this - just cap the extra port on the evaporator? If yes, does anyone happen to know what size / source for a cap?

    Thanks!
    Mike
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  2. mixedgas

    mixedgas Formula Junior
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    #2 mixedgas, Jul 30, 2025 at 9:28 AM
    I'm also not above getting a different TXV and not using the one they included with this 'kit'.
     
  3. Imatk

    Imatk Formula Junior

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    #3 Imatk, Jul 30, 2025 at 2:58 PM
    I don't know if they vary from year to year (I'm guessing they do?) but my evaporator did not have a port on the 90-degree elbow like you have pictured there.
     
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  4. Imatk

    Imatk Formula Junior

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    #4 Imatk, Jul 30, 2025 at 3:01 PM
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  5. mixedgas

    mixedgas Formula Junior
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    #5 mixedgas, Jul 30, 2025 at 3:54 PM
    Thanks for the response! I think I'm just going to plug it and see how it goes - seems some cars have those small pressure equalization lines and some dont even within the 308 production run. I think it takes a 1/8 inch thread cap.
     
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  6. Freddie328

    Freddie328 Formula Junior

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    #6 Freddie328, Jul 31, 2025 at 7:39 AM
    Externally equalized expansion valves have better control of the system superheat, as they take into account the evaporator pressure drop.
    Given how wheezy and imbalanced compared to the compressor size these evaporators are, which leads to pressure drops, you will degrade the performance with an internally equalized valve.
     
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  7. Imatk

    Imatk Formula Junior

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    #7 Imatk, Jul 31, 2025 at 7:45 AM
    Would it be better for him to just use the OG one? I mean we're just talking about copper wire here right?

    Anything to help that tiny little evap is a good thing.
     
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  8. Freddie328

    Freddie328 Formula Junior

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    #8 Freddie328, Jul 31, 2025 at 7:54 AM
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  9. johnk...

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    #9 johnk..., Jul 31, 2025 at 8:00 AM
  10. mixedgas

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    #10 mixedgas, Jul 31, 2025 at 8:55 AM
    Last edited: Jul 31, 2025 at 9:03 AM
    This is awesome, thank you very much! My original TXV shows sign of contamination (kind of crusty inside) and so I would prefer to replace it. I think I'll 'do this right' and track down an externally pressurized valve. I'm headed to Portland this weekend which is the heartland for vintage Volvo - I'll see if ipd or anyone up there has one. Thanks again! -Mike

    Oh, and while I'm thinking of it, if anyone in the future is reading this and looking to cap that port on their evaporator it is not a 1/8 inch fitting (too small) - I think it is 1/4 inch.
     

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