Odd thumping noises from under the hood WELL after the vehicle has been turned off.

JRav007

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So...I’ve noticed something very odd with my new Bronco Sport... I have experienced very odd shifting/clunking/banging sounds from under the hood well after the car is turned off.

First time I was in a location where I was in the Bronco for about a 45 minute time period waiting for an appointment. The car was turned off and after about 15 minutes I heard a very loud and pronounced clunking/shifting sound from under the hood. So loud it startled me! For the next 30 minutes it happened 4 or 5 more times...I honestly thought there was a squirrel or animal under the hood up in the engine.

Second time was today...my wife and I were hiking and came back to the Bronco after about an hour and a half for a break...got in the car and sat...DID NOT turn it on...and here came the clunking and thumping again! I’m glad she was there because I sounded crazy describing it after the first time.

Any thoughts? What could be going on under the hood over an hour after the vehicle is turned off that could be making such a weird racket? I’m almost at 1500 miles and have been following the break in protocol carefully...loving everything so far but this has me weirded out...
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fourthgear

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A call to the service dept. at your Ford dealer would get it looked at , mainly because it doesn't sound like it should be doing that , thats for sure .

I hear a sound anytime I open the door before starting , like a small fan starts up in the Engine compartment . I have looked in there & can hear it , but not sure what it is or exactly where it is . , its a pretty quiet sound , no banging , thats for sure .
 

Raymo

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I hear the same thing, but wasn't worried about it. Thought it was a relay for lights or something else.
 
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JRav007

JRav007

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I hear the same thing, but wasn't worried about it. Thought it was a relay for lights or something else.
The fact that it is occurring SO long after the vehicle is turned off is what really has me scratching my head. How long after the car is turned off are you hearing it?

Being that I’ve experienced it the only two times that I’ve actually been in the car for more than a few minutes after turning it off makes me wonder if it is clunking and banging all day and night when I’m not there.

Believe me...I know how crazy this sounds but I swear to ya...honestly sounds like a frigging animal brustling around under the hood to the point where I checked after the first time I heard it! The weather has been cold...could it be the engine cooling and settling or something?
 
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JRav007

JRav007

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A call to the service dept. at your Ford dealer would get it looked at , mainly because it doesn't sound like it should be doing that , thats for sure .

I hear a sound anytime I open the door before starting , like a small fan starts up in the Engine compartment . I have looked in there & can hear it , but not sure what it is or exactly where it is . , its a pretty quiet sound , no banging , thats for sure .
Im honestly trying to get some feedback and trouble shoot this before calling the dealership. “I’ve got a clunking sound that is happening randomly under the hood after I turn it off” is something that generally will open a massive can of worms at a dealership or garage. I don’t feel like a 6 month diagnostic trial and error repair approach to solve a problem that although weird, is probably (hopefully) no big deal.
 


Geelloo90042

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Wow!!..So you do have a real live bronco.

So there is nothing in the owner's manual that would explain that? I can only imagine a pump is running trying to do something as part of a normal operation..but I would check with the dealer.. hopefully those functions doesn't drain the battery after left alone for a long time period
 

Bobaloo

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The fact that it is occurring SO long after the vehicle is turned off is what really has me scratching my head. How long after the car is turned off are you hearing it?

Being that I’ve experienced it the only two times that I’ve actually been in the car for more than a few minutes after turning it off makes me wonder if it is clunking and banging all day and night when I’m not there.

Believe me...I know how crazy this sounds but I swear to ya...honestly sounds like a frigging animal brustling around under the hood to the point where I checked after the first time I heard it! The weather has been cold...could it be the engine cooling and settling or something?
You need to call in an exorcist.
 

AV99GT

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Can you record the sounds?

What I have noticed: After a drive. ~ 15 minutes later (just happened when I was out by the garage) I hear some hissing and what sounds like an actuator clicking a couple of times. This is up front, maybe it has to do with the DI pump.. But no banging or concerning noises.

Now in the back I also head some noises that I've heard on other cars that has to do with the OBD evap pump testing the system.

Lastly like others have said on other posts I too hear the headlight fans(?) go on 1) when opening the drivers door, 2)I have also heard it when Auto closing the windows with the lock remote button.
 

Jenma

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I have heard the active grill shutters close after the engine cools. 20 25 minutes or so.
 

Excape

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You need to call in an exorcist.
Does it have the CoPilot 360 Assist+?
Being in control systems myself, I've been trying to tell you guys...

Skynet had developed self-awareness. When its handlers realized this, they attempted to shut it down. In that instant, Skynet determined that all human beings were a threat to its own existence, deciding that the human race had to be exterminated.

Then again, anyone remember Christine?
 


DMEARC

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Some vehicles will run an emissions system check by pressurizing the fuel vapor recovery system and checking for leaks. It’s possible the Bronco Sport does this, but it’s just a guess.
 

Jenma

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Some vehicles will run an emissions system check by pressurizing the fuel vapor recovery system and checking for leaks. It’s possible the Bronco Sport does this, but it’s just a guess.
I have a friend with a Toyota FJ and he said exactly that. It would randomly pressurize the fuel system. We were discussing noise occuring hours after shut down and he brought it up.
 

13MikeH

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This may be relevant and may be way off base. I had a ranger long ago and it did something similar with an odd thump now and again. Dealers could never reproduce it. Long story short, it was a faulty check valve building up pressure. Had a mechanic ride with me, it went through it's paces after we parked at the garage. Took a day to fix. Hope that might help?
 

LCNM21

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I too hear this strange noise after sitting inside once the engine is turned off. Within 5 minutes, a "click", kind of a "thump" sound that last for less than four seconds from under the left side of the engine compartment. It will do it a few times while sitting there. Today, when checking the engine oil after sitting overnight, once I opened the doors, the noise was there again. Placing my hand on top of the plastic radiator shroud, I could feel a faint vibration as if a small motor was running the whole time. I don't know if this is a normal operation, but I've never owned a newer vehicle with this same issue.
 

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As for the fan noises, there seem to be cooling fans on each headlight shroud to keep the LED circuitry cool.

But the relay/solenoid clicking has me baffled, it occurs very randomly...it seems to affect the brake pedal resistance, I wonder if it has something to do with the accident avoidance braking system? It may be reacting to motion in front or behind the car.
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