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AC makes loud scraping noise

Discussion in 'Generation 1 Prius Discussion' started by BigEddie, Apr 5, 2015.

  1. BigEddie

    BigEddie Junior Member

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    This is a 2001 Prius - car runs great and the AC is fine. However, driving down the road, when the AC is turned on there is a noticeable scraping/ticking noise - sounds like it coming from under the hood.

    With the car parked, and the ignition ON, but without the gas engine running, there is no scraping noise.

    Can someone point me in the right direction for troubleshooting?

    Cheers
     
    #1 BigEddie, Apr 5, 2015
  2. hchu1

    hchu1 Active Member

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    I believe the 2001 has a belt driven compressor, it could be worn. A belt that is old will have numerous cracks on the belt and this could be the source of your ticking sound. The scraping sound could be associated with the belt as well or could be the clutch being noisy.
     
    #2 hchu1, Apr 5, 2015
    BigEddie likes this.
  3. BigEddie

    BigEddie Junior Member

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    hchu1,

    Thanks for the reply.

    The compressor is belt driven and I'm pretty sure it is off the serpentine belt (rather than a secondary belt).

    I tried inspecting this belt but it is down there in the engine bay - bunch of stuff in the way.

    Has anyone come across a decent procedure for R/R the belt, ie which components to remove so you can get a look and a hand down there? The Haynes manual is a bit of a disappointment in this respect.

    Cheers
     
    #3 BigEddie, Apr 5, 2015
  4. ChapmanF

    ChapmanF Senior Member

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    I wonder how much longer people will even bother trying to find stuff in Haynes etc. manuals when the real Toyota ones are right online at techinfo.toyota.com.

    Very easy to get to the compressor clutch and belt if all you do is turn the steering all the way to the right before you stop, then drop the right end of the plastic engine under cover. Don't even have to take all the engine cover screws out.

    All the steps you need (and more!) are covered in this thread. I say "and more" because that thread starts out by giving a complete procedure for replacing the compressor clutch, when in most cases if the clutch is slipping the buck-and-a-quarter shim kit is all you need, which is a much less involved operation.

    While you've got that engine cover off and everything's turned off, you can try to spin the pressure-plate part of the clutch by hand (the round disc with the two triangle shapes on it that looks like the face of the A/C compressor pulley). With everything turned off, the clutch should be released and you should be able to turn the plate smoothly and quietly by hand even though the pulley itself won't turn with it.

    If that happens, a clutch problem is probably all you have. If there's noise or roughness while you're turning just the pressure plate by hand, you might not have only a clutch problem.

    -Chap
     
    #4 ChapmanF, Apr 6, 2015
  5. BigEddie

    BigEddie Junior Member

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    Many thanks for that information, Chap.

    I'll give it a go and report back!
    Cheers!
     
    #5 BigEddie, Apr 7, 2015
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