AC works best when sitting still.

Discussion in 'Ask An Owner Operator' started by Edjahman, Nov 3, 2018.

  1. Edjahman

    Edjahman Medium Load Member

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    Hi.

    Peterbilt just did a warranty replacement on the AC compressor and now the AC works great while sitting still and only sort of lukewarm while driving.

    They are blaming it on the blend door actuator but it doesnt sound like that kind of problem to me, unless I'm wrong.

    What would cause the AC to work great while sitting still and so, so while driving?

    Thank you
     
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  3. 86mechanic

    86mechanic Medium Load Member

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    Could be overcharged.
     
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  4. Edjahman

    Edjahman Medium Load Member

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    Yeah I read that somewhere. I'll have to check that out.

    Thank you.
     
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  5. shogun

    shogun Road Train Member

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    Blend door actuator would only come into play when changing the temp settings from hot to cold or vice versa. If its overcharged it will be cycling every few seconds.
     
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  6. snowwy

    snowwy Road Train Member

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    My vote is undercharged.

    You've got enough to make it work at idle. But not enough for higher air flow through condensor and higher engine speed when driving. Which will impact high pressure readings.

    How often does the radiator fan cycle off and on? It'll be alot if overcharged. Not so much if under.
     
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  7. Ridgeline

    Ridgeline Road Train Member

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    The question I have is why did they replace the compressor?
     
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  8. shogun

    shogun Road Train Member

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    And sometimes you can hear the hiss of the expansion valve as it converts the liquid to gas if it’s undercharged.
     
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  9. Final Drive

    Final Drive Road Train Member

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    And dryer..
     
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  10. Espressolane

    Espressolane Road Train Member

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    This repair was not done correctly.
    Need to have the system checked.
     
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  11. Edjahman

    Edjahman Medium Load Member

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    The compressor was a warranty replacement from Paccar. The old one Failed after two and a half months.

    I'll just have to get it checked again, obviously.

    The fan cycles at a normal interval while fast idling. It doesn't cycle much while driving if at all.

    Thank you for your replies.
     
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