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High-pitched buzz/whine when engine is stopped

28320 Views 72 Replies 34 Participants Last post by  CuoreAlfa
Hi all,

I'm a fairly new owner of a '62 plate 170 TCT diesel.

I've noticed that when I turn the engine off, there's a high-pitched whining/buzzing noise coming from the engine bay somewhere. It doesn't matter if the engine's been run for a few moments or a half-hour or more. Is this normal? Has anyone else noticed it, and if so does anyone have any idea what it may be?

Just curious...

Thanks in advance,
Biggsy
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Discussion Starter · #5 ·
Well its comforting to know that I'm not the only one :)...
Still, it would be nice to know what's doing it; maybe I'll ask at the garage when its next in for a service (if I remember 'cos its ages 'til its due)
 

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do you hear it while still inside the car (as that's when I hear something aswell, think it's the fan for the interior temperature sensor) or do you hear it while ouside? if outside, it's likley vacuum escaping from somewhere in the circuit or even through the vacuum pump
 

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Discussion Starter · #7 ·
Its outside, and sounds like a motor or something, not the sort of hiss or sucking sound you'd get from a vacuum. I'm minded to think its got something to do with emissions - you know some sort of purge process. My main concern was if it was something unusual; other posts make me think not, just another quirk like the stop/start (or start-and-never-stop-except-randomly-when-I-feel-like-it) system
 
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I've noticed that when I turn the engine off, there's a high-pitched whining/buzzing noise coming from the engine bay somewhere. It doesn't matter if the engine's been run for a few moments or a half-hour or more.
Is this happening every single time you stop the engine?
I've had this on a handful of occasions, and it was the Xenon ballasts making the buzzing noise every time. Happened only in cold weather. It's normal, I think, but check with the dealer anyway next time you're in.
 

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Mine does it too. I thought that it was either the fuel pump or the air recirculation flap opening/closing. It does it if you turn on the ignition but don't start the engine too. My daughters VW Lupo does it when you open the door, but it's not so high pitched.
 

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If it's specific to TCT models then it could be the gearbox priming itself - a similar noise occurs on Fiat Dualogic auto gearboxes.

However if it's on manual Giulietta's too, then I'd put it down to electronic systems shutting down. My Stilo humms for a few seconds when stopping the engine and then clicks loudly and the humming stops. Always done it.
 

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Was jump starting the wife's CRV and I heard the whine from my manual diesel with the bonnet open.
It sounded like something release pressure then closing a valve.

In fact, although it sounded nothing like it, it reminded me of the power transfer unit on an A319/320 that you hear just after push back from the gate.
 

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Old thread....
My QV does it - so nothing to do with TCT. It's a cross between a buzz and a humm! Seems to come from the belt end of the engine. It lasts about 5 mins after engine switch off and gradually gets quieter and quieter. The weird thing is I've had the car for two years and its only just started doing this.

It's nothing like the same noise as you get from the 156 etc when you shut down - I think that's more to do with air flaps etc.
 
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mine does it too! I thought it was something to do with the diesel injection system but could be a vaccum thing going on. It lasts for about 30 seconds after turning the ignition off!
 

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that'll be vacuum escaping, used for the brakes and the turbo control
sounds more electrical to me

mine does it too! I thought it was something to do with the diesel injection system but could be a vaccum thing going on. It lasts for about 30 seconds after turning the ignition off!
In my case more like 5 -10 mins, gradually getting quieter
 
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