Whistle / screech from throttle or head after car off

[shaloot]

First time ever hearing this. Drove for 30 miles, parked in garage, turned off car, popped hood to connect battery tender. Started hearing this weird whistle / screech sound every so often. First it seemed to coincide with when I stepped in front of the proximity sensors but then it was just random. Searching here and listening closely it seems maybe it’s the throttle doing some weird sort of tests or adjustments.
Anybody that can put my mind at ease? This went on for like 10 mins after the car was off. 20 mins later it’s stopped completely. I’ll be posting a video once at home and it actually uploads.

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[shaloot]

Video

 

[Eastwood]

Replace the battery in your smoke detector, I can’t hear anything.

 

[shaloot]

lol it’s giving me the same vibes as that but it’s def the car haha

sounds better than this post about the same question, but assuming same thing
https://www.supramkv.com/threads/engine-noise-after-shut-off.14554/

 

[lucky phil]

lol it’s giving me the same vibes as that but it’s def the car haha

sounds better than this post about the same question, but assuming same thing
https://www.supramkv.com/threads/engine-noise-after-shut-off.14554/

It sounds very much like a louder version of a motorcycle fuel tank vent squealing after the engine is shut off and the bike is parked. The fuel in the tank heat soaks from the engine heat and the tank starts to vent as the pressure builds up and lifts the vent valve off it's seat and it squeals or whistles intermittently as the pressure then vents into the vent canister. This might be the same with the HP fuel regulator dumping excess rail pressure as the fuel in the rail heat soaks from engine heat and the pressure goes up. Try starting the car and running it for a minute or so from cold and see if it still happens without any real engine heat. I guess if you could log the HP fuel pressure when the engine shuts down it might show something.
Phil

 

[shaloot]

It sounds very much like a louder version of a motorcycle fuel tank vent squealing after the engine is shut off and the bike is parked. The fuel in the tank heat soaks from the engine heat and the tank starts to vent as the pressure builds up and lifts the vent valve off it's seat and it squeals or whistles intermittently as the pressure then vents into the vent canister. This might be the same with the HP fuel regulator dumping excess rail pressure as the fuel in the rail heat soaks from engine heat and the pressure goes up. Try starting the car and running it for a minute or so from cold and see if it still happens without any real engine heat. I guess if you could log the HP fuel pressure when the engine shuts down it might show something.
Phil

Thanks Mr. Phil for the suggestions. Car is in storage now a short ride from my house, but I’ll take it out again later this week to do a pre-winter detail and fill up with fuel and stabil, so will be checking then.
I agree that the randomness of the length & timing of the sound could be some sort of pressure releasing from somewhere, I THINK it was coming from the throttle body or close to there. That video I linked the dude seemed to think that filling up his coolant resolved the issue… I didn’t check my coolant level but I had no warnings and temp didn’t go above the normal halfway point at any time.
Never heard it before, and I can’t think of anything unique about my drive last night. Only did one hard pull halfway up third gear onto highway, gentle driving for the last 10 mins before parking up on flat stoppers.
i don’t normally drive it when it’s this cold (was 40 degrees F when this happened), not sure if that’s any factor.
Such a weird thing to hear strange noises from engine bay after you turn a car off lol

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