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355 Belt sound higher rpms

Discussion in '348/355' started by amazingtrails, Oct 10, 2025 at 12:01 PM.

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  1. amazingtrails

    amazingtrails Karting

    Jan 4, 2025
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    #1 amazingtrails, Oct 10, 2025 at 12:01 PM
    Hello, I own a 1997 f355 spider (gated manual). 36k miles. Car runs great. However lately i've noticed a belt type "shuffling" noise at higher RPMs. I don't hear it idling. It is fairly loud in higher gears and above 3-4k rpms. The exhaust often drowns out the sound especially when my windows and top are down. Thoughts?
     
  2. yelcab

    yelcab F1 World Champ
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    Nov 29, 2001
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    #2 yelcab, Oct 11, 2025 at 8:49 AM
    When is your engine out service?
     
  3. amazingtrails

    amazingtrails Karting

    Jan 4, 2025
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    #3 amazingtrails, Oct 11, 2025 at 9:08 AM
    it’s been 3 years according to the previous owner. I was hoping to wait another 2 years.
     
  4. yelcab

    yelcab F1 World Champ
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    #4 yelcab, Oct 11, 2025 at 3:23 PM
    You have to figure out which belt is doing the shuffling noise. There are 5 belts. Two timing belts, one AC belt, one Alt / water pump belt, and one PS belt. They all have tensioners that may be too loose. From the bottom of the car, you can feel for tension on two belts, from the top you can access one belt, and there is no way to check tension on the timing belts unless you ... remove the engine. And by then, you might as well change them and the tensioners.
     
  5. amazingtrails

    amazingtrails Karting

    Jan 4, 2025
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    #5 amazingtrails, Oct 11, 2025 at 3:29 PM
    Other than the annoying noise is it a problem if I just do nothing and wait for the next engine out service in 2 years?
     
  6. yelcab

    yelcab F1 World Champ
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    #6 yelcab, Oct 11, 2025 at 3:38 PM
    Depends on what belt... You cannot ignore anything bad with the timing belts. The result of a timing belt failure is an engine replacement.
     
  7. amazingtrails

    amazingtrails Karting

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    #7 amazingtrails, Oct 11, 2025 at 3:43 PM
    Right but in order to even check the timing belt tension I would need an engine out so that's a bit of a dilemma.
     
  8. yelcab

    yelcab F1 World Champ
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    #8 yelcab, Oct 11, 2025 at 3:55 PM
    Check the other three belts first ...
    Then decide.
    Nobody ever said owning a F355 was going to be easy, or low cost. Fun, yes.
     
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  9. amazingtrails

    amazingtrails Karting

    Jan 4, 2025
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    #9 amazingtrails, Oct 11, 2025 at 4:04 PM
    Thanks for your help. By checking them do you mean just pulling on them to make sure they are tight ?
     
  10. yelcab

    yelcab F1 World Champ
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    #10 yelcab, Oct 11, 2025 at 4:17 PM
    Technically, there is a frequency spec for each belt. However, that is pretty hard to do with engine in the car. So, do it the old fashion way.

    1. The PS belt is small, and must be really tight. Push on it, it should not give any deflection at all.
    2. The AC belt is second smallest and should give 1/4 inch deflection.
    3. The Alt-waterpump belt is big, and long. That should give you 1/2 inch deflection at the long side.

    This is just ball park, unscientific, take-it-with-a-grain-of-salt advise.

    While you are under there, check to make sure all nuts bolts fasteners tensioners are nice and tight.
     
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