2.7 engine noise while engine is off

[Onestepmore]

I was just back from a hard run at the Missouri 100 Acre Rally checking my air filter (lot of dust) and I heard this...anyone have any ideas of what this is...???

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[jtgensler]

probably a relay or something in the electrical system.
I get an occasional whirring sound or click as something turns off or times out while I have the hood up

 

[Ducati1098]

Something going through it's shut down procedure. Nothing to worry about.

 

[Onestepmore]

probably a relay or something in the electrical system.
I get an occasional whirring sound or click as something turns off or times out while I have the hood up

Thanks for the quick reply...the dealer this morning said it might be the emergency lights I installed running off auxiliary switch #6...I told the service manager I'm sure that's what is causing the noise. Hence why I reached out to you guys

 

[Brian_B]

There are a lot of things that run under the hood with the key off. The headlights have cooling fans, there are some pumps that can continue to circulate after shutting off. There are fuel pumps that will pre-prime before start up. Especially if you have the proximity unlock - my wife's Sport will start clicking and humming just by walking near it.

 

[Diller]

I had the same thing on a hot day here in Florida while washing my Bronco. Traced it to the AC system. Seems to be the pressure bleeding through the expansion valve as the ambient heat expands the refrigerant.

 

[Onestepmore]

I had the same thing on a hot day here in Florida while washing my Bronco. Traced it to the AC system. Seems to be the pressure bleeding through the expansion valve as the ambient heat expands the refrigerant.

Thanks for replying...you would think the dealer would be aware of such things.

 

[RedRider]

https://www.bronco6g.com/forum/threads/beep-whistle-after-driving-when-engine-is-off.109663/
https://www.f150forum.com/f118/whistle-sound-when-truck-not-running-412016/index2/#post6029741

Seems to be a pretty common thing with EcoBoosts in the F-150, where it is has been attributed to A/C low side system pressure exceeding the high side pressure. The threads linked above have some leads you can chase down. I think Diller's tracing it back to the A/C system is spot on and aligns with the consensus that it is A/C system related.

 

[Onestepmore]

https://www.bronco6g.com/forum/threads/beep-whistle-after-driving-when-engine-is-off.109663/

Also seems to be a pretty common thing with EcoBoosts in the F-150, where it is has been attributed to A/C low side system pressure exceeding the high side pressure. The thread linked above has some leads you can chase down, although I don't think anyone has confirmed with 100% certainty the cause.

Great...Thank you!!!

 

[Diller]

Thanks for replying...you would think the dealer would be aware of such things.

Here's a video of mine. I just happened to have my hand on the refrigerant line at the front of the engine bay while videoing so I felt it in the line. Started the engine, ran the AC for a few minutes then turned it off and the noise was gone. I've never seen this with 134 or 12 systems, so it may be just something with this new refrigerant.

 

[wgw]

There are a lot of things that run under the hood with the key off. The headlights have cooling fans, there are some pumps that can continue to circulate after shutting off. There are fuel pumps that will pre-prime before start up. Especially if you have the proximity unlock - my wife's Sport will start clicking and humming just by walking near it.

 

[CarGuy]

Most of my vehicles make a symphony of sounds when unlocked/locked. Quite common on newer vehicles.

 

[Grift3r]

Its obviously broken beyond repair. Best sell it for scrap and gimme that hard top.

 

[CitrusBronco]

I was just back from a hard run at the Missouri 100 Acre Rally checking my air filter (lot of dust) and I heard this...anyone have any ideas of what this is...???

My 2.3 makes a sound like that sometimes when I’m near it. Usually when washing it and the key is in my pocket.
I think the Bronco is talking to me. Like let’s go for a run I’m ready.
If I put the key 10’ or so away it stops talking to me.

 

[BeachBroncoBabe]

Here's a video of mine. I just happened to have my hand on the refrigerant line at the front of the engine bay while videoing so I felt it in the line. Started the engine, ran the AC for a few minutes then turned it off and the noise was gone. I've never seen this with 134 or 12 systems, so it may be just something with this new refrigerant.

S

Here's a video of mine. I just happened to have my hand on the refrigerant line at the front of the engine bay while videoing so I felt it in the line. Started the engine, ran the AC for a few minutes then turned it off and the noise was gone. I've never seen this with 134 or 12 systems, so it may be just something with this new refrigerant.

Sounds like a duck...could be the Jeep ducks playing tricks on you

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