Ferrari 348/Mondial T squealing noise during warm up | FerrariChat

Ferrari 348/Mondial T squealing noise during warm up

Discussion in 'Technical Q&A' started by Big Block F, Jul 28, 2017.

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  1. Big Block F

    Big Block F Rookie

    Jun 19, 2017
    15
    Perth WA
    The Mondial T is getting closer to being back on road.

    1991 model car. Motronic 2.5.

    I have noticed a high pitched squealing which becomes apparent during the warm up cycle.

    Upon start from cold, no squeal, after around 4 - 5 minutes the squeal begins, not too loud hut noticeable.

    If you rev the engine, the squealing is more prominent but not as much as expected with the increase in engine revs. The squealing grows in volume.

    Once the engine has reached full operating temperature, the squealing is gone.

    If you switch off the engine and then restart, maybe a momentary squealing then no more.

    I have tried depressing the clutch etc, this does not lessen or increase the squealing.

    The squeal appears to come from an area to the rear of the motor or maybe even under the intake plenum.

    I am wondering if the squealing is actually a vacumm leak or some sort of vacumm valve operation that takes place during the warm up cycle.

    Any suggestions?
     
  2. StuR

    StuR Formula Junior

    Jun 14, 2005
    561
    UK Buckinghamshire
    Full Name:
    Stu R


    It's not the alternator belt?


    Sent from my iPhone using Tapatalk
     
  3. Big Block F

    Big Block F Rookie

    Jun 19, 2017
    15
    Perth WA
    Thank you for the input.


    Definitely not the alternator belt.

    I sprayed some WD 40 on the belts with the engine running but no change.

    The noise starts after the engine runs for 5 or so minutes, then disappears as the engine gets to what is probably full operating temperature.
     
  4. AceMaster

    AceMaster Three Time F1 World Champ

    Feb 6, 2009
    34,777
    Ontario, Canada
    Full Name:
    Mike
    Is WD 40 safe for the belts?
     
  5. Big Block F

    Big Block F Rookie

    Jun 19, 2017
    15
    Perth WA
    Doesn't matter, all will be changed at the next service, which will take place very soon.
     
  6. Wade

    Wade Three Time F1 World Champ
    Owner

    Mar 31, 2006
    32,793
    East Central, FL
    Full Name:
    Wade O.
    Can you narrow it down to a general/specific area of the engine bay?
     
  7. Big Block F

    Big Block F Rookie

    Jun 19, 2017
    15
    Perth WA
    Sounds like right in the centre, upper area (maybe a little towards the back), possibly under the intake plenum.

    The noise starts after 5 or so minutes of running from cold, then gets progressively louder before gradually disappearing at what may be full warm up.
     
  8. Wade

    Wade Three Time F1 World Champ
    Owner

    Mar 31, 2006
    32,793
    East Central, FL
    Full Name:
    Wade O.
    To me, I interpret a "squealing noise" as something that a bearing does. A whistle or hissing sound for vacuum or air leaks.
     
  9. Aus_yz

    Aus_yz Karting

    Sep 5, 2015
    52
    Australia
    Full Name:
    Mika
    Check your water pump remove the belt and check for movement in shaft and if it spins smoothly but still with a little seal drag . Any play in shaft replace it
     
  10. Wade

    Wade Three Time F1 World Champ
    Owner

    Mar 31, 2006
    32,793
    East Central, FL
    Full Name:
    Wade O.
    Wish it were that easy. On the 3.4 motor (348 and Mondial t) there's a single belt that runs all four camshafts and the water pump. And you need to pull the motor to removed that same belt (without cutting it off).
     
  11. ernie

    ernie Two Time F1 World Champ
    Lifetime Rossa Owner

    Nov 19, 2001
    22,614
    The Brickyard
    Full Name:
    The Bad Guy
    From what you describe my guess is either of the following or any combination:

    1) water pump bearing is failing
    2) tensioner bearing failing and/or idler bearing failing
    3) tensioner bearing for the alternator failing
    4) lower cam pulley drive bearing failing
    5) all of the above
    6) anti-skip shoes rubbing on the cam belt
     
  12. BillP00

    BillP00 Formula 3
    Owner

    Apr 23, 2007
    1,933
    Northern VA
    Full Name:
    Bill
    +1 I had a similar noise on my '86 Mondial 3.2 Cabriolet near the waterpump pulley and it also showed signs of wear. The pulley and tensioner bearings were replaced and all belts were adjusted and the sound was gone.

    Bill P.
     

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