Weird Sound When Auto/Stop or Vehicle Off

[SportbackLegacy]

2018 Buick Regal Sportback Preferred and my vehicle makes a loud whirring noise when the vehicle shuts off or when I turn the vehicle off. Can anyone tell me what that noise is coming from?

 

[ZB Commodore Owner]

Could be the electric cooling fan(s) spinning down. I haven't taken much notice with my ZB Commodore but I know my VY Commodore there's two fans, one large and one small. One runs if the engine is above a certain temperature and the other runs whenever the air con is on. You often hear the air con one spin down after you shut then engine down.

 

[shs92645]

My GS made the noise you mention which was one of the reasons that I installed my Smart Stopstart module shortly after buying the car. Now I peacefully hear the idling V6 when the car is stopped. As the old saying goes….music to my ears.

 

[ZB Commodore Owner]

My GS made the noise you mention which was one of the reasons that I installed my Smart Stopstart module shortly after buying the car. Now I peacefully hear the idling V6 when the car is stopped. As the old saying goes….music to my ears.

The V6 sound is indeed music, and not just at idle.
Fortunately Mr Holden saw fit to give us a switch to disable ASS. ASS is an Ass of an idea.

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[abizzle]

The V6 sound is indeed music, and not just at idle.
Fortunately Mr Holden saw fit to give us a switch to disable ASS. ASS is an Ass of an idea.

What is this ASS you speak of? Ohhh yeah, that’s that annoying feature that shuts off the engine when the car is stopped. I almost forgot my car used to do that. I have been enjoying burning all that additional fuel!

 

[SportbackLegacy]

I’m thinking fan or coolant because it makes the noise even after it’s been parked.

 

[FavaBean]

2018 Buick Regal Sportback Preferred and my vehicle makes a loud whirring noise when the vehicle shuts off or when I turn the vehicle off. Can anyone tell me what that noise is coming from?

If the sound is not the normal fan sound and more a squelching sound, it's believed to be the auxillary pump.

I brought mine in last week for this and unfortunately since it happens so infrequently, they were not able to replicate it at the dealer. I even went for a 20-minute ride trying to replicate it with a tech and the sound did not happen. (Of course it happened two times the next day after I got my car back).

I've noticed as it's starting to get cooler at night, this issue happens more and more often now that I'm starting to use heat instead of cool.

 

[DrFaustus]

I'm pretty sure I get the same noise. I've been trying to figure out what it is exactly. I've been wondering if it purged water from the A/C system. Since I hear it only for a moment, and only after the system turns off.

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[FavaBean]

Mine has squelched for 10-15 seconds at a time. Restarting the car, driving away and/or altering the temperature does not shut the noise down. You just need to wait until it's done.

When it happens, I feel everyone is staring at me at the traffic light... it's quite embarrassing.

 

[abizzle]

Over on the Cascada forum there are people discussing a squealing sound when the car is turned off. Problem was discovered to be the valve cover and what I’m assuming to be air leaking out. It’s a long shot, but the issue seemed similar to what y’all are discussing.

 

[jmf432]

If you're only hearing it during a stop/start event, then it might just be the aux pump and is "working as designed."
https://static.nhtsa.gov/odi/tsbs/2018/MC-10137340-9999.pdf
I can't remember hearing anything with mine once I turn it off though so maybe your issue is something different.

 

[DrFaustus]

I thought it may be something like that. Does anyone know what that pump does, exactly? Is there a way to turn it on and off for testing? I know I could do that kind of thing with my VW and the VCDS software on my laptop.

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[94cruiser]

Thanks for that link.

This does not mention what kind of sound is it.

Is it the
normal fluid transfer pump sound
or
cutting in and out and much louder presume because of air?

It almost sounds in a way where the pump would break away from the shaft and the shaft was spinning but not the pump.

Makes sense?
The way the buletin is written it covers ALL sounds.

And yes, it is insanely weird when it happens and you may question what was that.
not to mention a prospective buyer may walk away.

 

[FavaBean]

For me, the sound is usually accompanied with a rushing fluid sound. I'm starting to think that maybe there IS air in the system. Is there a way to burp the system to ensure there is no air in the coolant lines? I also need to check the fluid level in the overflow reservoir to ensure it's up to the line.

 

[94cruiser]

Based on reading the forum I'm seeing few different versions:
- electrical noise
- electrical noise with fluid slush
- electrical noise abrupt with louder noise sonstant or interrupted
(based on my personal experience with using portable battery operated transfer pumps they will run louder if not submerged fully with liquid)

I'm fine with the first two. The third does not sound right either by design (poor R&D design which allows air to accumulate), manufacturing defect (badly manufactured component which traps or introduces air into the system), or bad install (badly assembled product)

 

[KingDapostrophe]

Chiming in to say that I experience a noise when ASS engages. It's more of a medium "hum" sound, sometimes accompanied by a fluid rushing sound coming from somewhere behind the dash. I read on a different thread a while back that the sloshing was just coolant and my coolant level might be slightly low (mine is a tad below the max line). The humming sound I'm experiencing doesn't worry me at all, it's almost exclusively when I'm running climate during ASS. Sometimes I will get that sound when I shut everything off, and it continues for a few seconds before it stops.

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[SportbackLegacy]

Still trying to figure it out. I got an error code P3056 today.

 

[94cruiser]

The hum sound or fluid slush sound I'm fine to be with.
It's the loud sound as if the pump is gurgling pumping air is where I have an issue with.

 

[Tourxwagon18]

I just got back from the dealer and the noise is in fact the AUX pump and is normal. So they didn't fix it. The weird thing is that this noise is new so I don't know why it just started all of the sudden but they don't seem to be concerned with it.

 

[jmf432]

I just got back from the dealer and the noise is in fact the AUX pump and is normal. So they didn't fix it. The weird thing is that this noise is new so I don't know why it just started all of the sudden but they don't seem to be concerned with it.

Are you using heat now and weren’t before? You should only hear it when you have heat running during an auto stop.