Whining sound when Turning off engine

Discussion in 'Engine, Gearbox, Exhaust and Air Intake' started by Dedespo, Aug 8, 2014.

  1. Dedespo

    Dedespo

    Messages:
    208
    Location:
    Athens, Greece
    Car:
    UR 197 Fatty
    I've noticed a high pitched whining sound when turning off the engine which starts high-pitched and pitch lowers as time goes by, sound fades away within ~ 3 seconds.

    Cams? The whine only appears when switching off, never heard it in motion or revving.

    Belts changed 5k miles ago.
     

  2. Jimmy

    Jimmy Good cop Administrator

    Messages:
    6,423
    Location:
    Leeds, W Yorks
    Car:
    R27 #243
    If it only happens when switching the engine off, could it be the fan??
     
  3. Dedespo

    Dedespo

    Messages:
    208
    Location:
    Athens, Greece
    Car:
    UR 197 Fatty
    No mate, its not the fan. In any case, the fan would not turn-off when turning off the engine, it's the other way around usually.

    My sound disappears within 3 seconds of turning off the engine. It's a discreet sound so i guess when idling its masked by other engine sounds and once i turn-off it's the only sound left and therefore noticeable until it winds down.
     
  4. Chris

    Chris Bad cop Administrator

    Messages:
    10,546
    Location:
    Needham Market
    Car:
    LY 200t
    Id be inclined to say fan belt, they make a whine sometimes.
     
  5. Dedespo

    Dedespo

    Messages:
    208
    Location:
    Athens, Greece
    Car:
    UR 197 Fatty
    Maybe you can enlighten me but i would think that if the radiator fan is on when you have reached your destination and park, it would stay on for a bit more after turning the engine off and not turn-off simultaneously unless its a coincidence which in my case it's not, it's every time.
     
  6. Chris

    Chris Bad cop Administrator

    Messages:
    10,546
    Location:
    Needham Market
    Car:
    LY 200t
    Depends how hot the engine is.
     
  7. Dedespo

    Dedespo

    Messages:
    208
    Location:
    Athens, Greece
    Car:
    UR 197 Fatty
    Of course it depends on engine temp and that's what i'm saying, if the car is hot enough for the fan to work while its underway and breathing air, it sure would be hot enough for the fan to keep working when it comes to a hault and therefore not turn off when you turn off the engine. Unless it's engine driven which i highly doubt. So my sound must not be fan-related.
     
  8. Jimmy

    Jimmy Good cop Administrator

    Messages:
    6,423
    Location:
    Leeds, W Yorks
    Car:
    R27 #243
    I'm no mechanic so it was a bit of a guess with it possibly being the fan to be honest. If the engine is hot after a drive and you come to a standstill, my (limited) understanding is - because the engine is no longer getting any cooling from moving air, the fan kicks in to draw in air whilst idling?

    If you then switch the engine off, I assume that the fan would also wind down (possibly the whine you've experienced). The engine wouldn't necessarily require the cooling from the fan as it's no longer operating?

    I might be wrong, so if anyone with better knowledge than I have puts me right, fair enough :smiley:
     
  9. Chris

    Chris Bad cop Administrator

    Messages:
    10,546
    Location:
    Needham Market
    Car:
    LY 200t
    You pretty much just typed out an identical post to what I wanted too :smiley:
     
  10. Jimmy

    Jimmy Good cop Administrator

    Messages:
    6,423
    Location:
    Leeds, W Yorks
    Car:
    R27 #243
    :smiley: great minds and all that! We still might be totally wrong about what's causing the whine though!!
     
  11. Foxspeed

    Foxspeed "the new red baron" Moderator

    Messages:
    15,443
    Location:
    sat behind a laptop over-moderating...
    Car:
    ford mustang shadow gt v8
    just pull the fuse for the fan and see if the noise disappears...
     
  12. Chris

    Chris Bad cop Administrator

    Messages:
    10,546
    Location:
    Needham Market
    Car:
    LY 200t
    Atleast the Clio genius foxspeed hasn't completely dismissed our thoughts haha :smiley:
     
  13. Foxspeed

    Foxspeed "the new red baron" Moderator

    Messages:
    15,443
    Location:
    sat behind a laptop over-moderating...
    Car:
    ford mustang shadow gt v8
    iirc when you switch the engine off it kills the cooling fan...but it would still run down (ie make a noise) when the ignition switched off if it was running say for the air-con condenser or cooling the engine
     
  14. Craig211

    Craig211

    Messages:
    761
    Location:
    New Deer, Aberdeenshire
    Car:
    2011 Clio renaultsport 200(MILF)
    It's the fan, I had this same query a while back so after a drive I got home left car switched on then got someone else to switch it off whilst looking in the engine bay and as soon as the engine stops the fan winds down, I think it's because when you open the door auxilary power is killed i.e lights radio wipers etc
     
  15. Dedespo

    Dedespo

    Messages:
    208
    Location:
    Athens, Greece
    Car:
    UR 197 Fatty
    I see what you mean now, but the sound doesn't just get quieter , it disappears altogether. Fan sound is very distinctive anyway and i am sure it's not that. Sorry for over-analyzing :bash:
     
  16. Foxspeed

    Foxspeed "the new red baron" Moderator

    Messages:
    15,443
    Location:
    sat behind a laptop over-moderating...
    Car:
    ford mustang shadow gt v8
    as said you need someone else to switch it off while you find the cause of the noise
     
  17. Dedespo

    Dedespo

    Messages:
    208
    Location:
    Athens, Greece
    Car:
    UR 197 Fatty
    Update:

    This high pitched noise can now be heard not only when turning off the engine (in which case it wound down and stopped as if something working in a spinning manner was turning off) but also in random maneuvering or generally slow speed stop & go (short whines). I am starting to think it might be some pump which is working under strain. What pumps do we have that might be making this sound? Or any other thoughts on what else it might be?
     
  18. Chris

    Chris Bad cop Administrator

    Messages:
    10,546
    Location:
    Needham Market
    Car:
    LY 200t
    Are you using the air-conditioning?
     
  19. Dedespo

    Dedespo

    Messages:
    208
    Location:
    Athens, Greece
    Car:
    UR 197 Fatty
    No, air-conditioning always off.
     
  20. Dedespo

    Dedespo

    Messages:
    208
    Location:
    Athens, Greece
    Car:
    UR 197 Fatty
    Update:

    Still haven't gone to my mechanic to look this up because he was out of town with a racing team.

    I tried to locate the source of the sound this morning while having someone else turning it off. I'm pretty sure its coming from the left side as i look from the front so there is a possibility of it coming from the belts. (as per previous owner, belts have been changed 6k km ago). I took a video, will upload once i'm home this afternoon. In the start of the video you can hear the same sound randomly giving out a small squeek and then when i power off you can hear the full orchestra.
     

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