2021 Ford Bronco Sport Thumping/Flapping noise

[Bronco Blue]

Fyi.. here is what Ford has to say:

SSM 51874 2021-2023 Bronco Sport, 2020-2023 Escape - Rattle Or Flapping Noise From The Rear Air Extractors

Some 2021-2023 Bronco Sport and 2020-2023 Escape vehicles may exhibit a rattle or flapping noise coming from the rear air extractors while driving. This may be due to the normal operation of the rear air extractors. To determine if this is a normal condition, perform a road test at 40 mph (65 km/h) or above. Inspect if the noise is coming from the rear extractors. During the road test alternate air conditioning (A/C) between fresh mode and air re-circulation mode. If the noise is eliminated when the A/C is in fresh mode, this is considered a normal characteristic of the vehicle and no repairs should be performed.

Yeah my dealership told me it was normal although I strongly disagree because I’ve had 2 non-Ford SUVs in my life so far that never made that noise. It’s really annoying.

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[Bronco Blue]

There are engineers in almost every sizable company who focus on cost reduction. Even before a product is introduced on the market, there are already people working on ways to make it less expensive.

I realize that this has been frustrating for you but to assume this part was introduced without testing it is purely an emotional response. The cost of a recall of any kind far outweighs the testing needed to prove the function. That is not to say that the testing always exposes every possible way that a part could fail, or just be annoying in this case. Again there are people who spend their entire careers just thinking about how something could fail and designing tests to mitigate those failures.

Apparently there are times/examples of this part making noise. It is not very widespread or there would be more evidence of it here on the forum. I seem to remember some talk about noises from the cargo area but nothing that has been brought up consistently. Maybe it is just something to do with the parts on your BS?

I think more do them, they just either don’t hear it, they were told it was normal, or they think it’s normal and it doesn’t bother them. The 22 Escape I had before my BS did it as well. It’s really annoying and I tried to show my service guy the thread of how people were getting it to stop, but they won’t do it because Ford said iTs NoRmAl ?.

Which I call bs since I’ve owned two non-Ford suvs and they didn’t flap. I’ve also been in other suvs, Fords and non-Fords and they never flapped. Also to make it worse, I had an 07 Dodge Caliber at one time and everyone knows just how cheap Chrysler was at that time and it didn’t flap either.

 

[69cuda340s]

When I first got the car, I couldn't stand the clicking from the faulty park release cable.

My Park Release Cable started making faint clicking noise around 1,500 miles. But some times it went away then came back. I noticed Ford revised the cable twice during 2022 and mine is a '21. I ordered the lasted revised cable swapped it in now silence zero noise from that cable. Didn't bother with dealer they would say normal not doing anything and even if they would fix it they would not do it right. Oh and ordered cable online like $50 shipped to my house.

 

[Glamdring70]

Didn't bother with dealer

That's the right way to handle some things. It's not worth being out the car for a diagnosis day and a follow up fix day. I need a small piece of weather stripping replaced. I think I am doing the same for that and just fixing it myself. Warranty would work fine but it's not worth the inconvenience for small stuff.

How difficult was the cable? Pull the battery to do it?

 

[69cuda340s]

That's the right way to handle some things. It's not worth being out the car for a diagnosis day and a follow up fix day. I need a small piece of weather stripping replaced. I think I am doing the same for that and just fixing it myself. Warranty would work fine but it's not worth the inconvenience for small stuff.

How difficult was the cable? Pull the battery to do it?

For cable had to pull battery and pull left side dash panel. Several hours not easy. There was some clip that holds pull string to cable that caused me grief. Prob easier if you order new pull string and what ever is required to fasten it to cable do that ahead of time. But revised cable is 100 percent silent so glad I did it.

 

[KRPTX]

This problem reminds me of a check valve that is over-sized. A fix might be to seal off one side thereby making the other side stay open? I wonder if taking them off could encourage air to come in and bring dust and, hopefully not, Carbon Monoxide from exhaust fumes into the car.

 

[Bluesteelworx]

I wonder if this could be what's allowing exhaust fumes into th cab of my sport. It's been to the dealer twice and they check the exhaust system for leaks and say it's fine.

 

[Sldavid]

Ever since I purchased my Bronco Sport new, I have experienced an annoying flapping/thumping noise coming from the rear cargo area both left and right side. The noise presents itself when traveling over 40 mph. It was hard to pinpoint the source as I believed it was coming from underneath the vehicle. With it not making any noise below 40 mph, I thought it had to do with something that was flapping caused by wind speed. I focused under chassis covers that are mounted below the fuel tank and extending to the rear fender outer wheel wells. Noting I did would eliminate the problem. Finally, I crawled into the cargo area while someone else drove the vehicle over 40 mph. I located the source of the noise coming from the cargo area left and right trim panels. There are two molded in vents on each side where I could hear the noise coming from. Behind these panels are what is referred to as the "rear Air extractors". These are basically plastic vents with rubber flaps that allow air to exit the vehicle cabin for air circulation. I removed the inner trim panels and a lower exterior trim panel to expose an opening large enough to fit my hand between to access the air extractor. I then pulled on the flaps to tear them away from the vent. There are 3 per each side. They are made of very thin, .018', flexible rubber. What was happening was that air moving over and in between the outer fender wells caused these rubber pieces to flap resulting in this constant thumping/ flapping noise. I put the trim panel back in place and test drove the vehicle, and problem was solved. No more thumping/flapping over 40 mph. In my opinion, this is clearly a design defect caused by using a method to make the function of venting cabin pressure the cheapest way possible with clearly no testing. This should have been caught during design testing. There are so many cheap shortcuts Ford has made to lower their cost and not provide a proper function that I won't go into further in this thread. Regarding the function now of these air extractors without the rubber flaps; it will make no difference without the flaps because the vents are covered behind insulation, so they were nonfunctional anyway. hope this help anyone else struggling with this problem. There are plenty of videos out there that show how to remove the inner trim panels.

Hi. Very informative. Can you please either tell me how you removed it safely or send me the video link showing the same. I don’t want to break anything. Thank ok

 

[RSH]

Interesting, I have a 2021 and have not heard any thumping or flapping noises.
I also have not had any noise issue with the parking brake cable or have exhaust fumes in the cabin. I did have electrical issues, they were resolved with a new battery, since then I have not had any problems other than the random rear brake moan which I can modulate, in fact I did it this morning, I just pressed the brake pedal a little harder and no noise.

 

[Buskkus]

Fyi.. here is what Ford has to say:

SSM 51874 2021-2023 Bronco Sport, 2020-2023 Escape - Rattle Or Flapping Noise From The Rear Air Extractors

Some 2021-2023 Bronco Sport and 2020-2023 Escape vehicles may exhibit a rattle or flapping noise coming from the rear air extractors while driving. This may be due to the normal operation of the rear air extractors. To determine if this is a normal condition, perform a road test at 40 mph (65 km/h) or above. Inspect if the noise is coming from the rear extractors. During the road test alternate air conditioning (A/C) between fresh mode and air re-circulation mode. If the noise is eliminated when the A/C is in fresh mode, this is considered a normal characteristic of the vehicle and no repairs should be performed.

My wife and I just purchased our Bronco and noticed this noise. Glad to know they designed it this way, but the noise can be distracting...

 

[Shumax]

My 2024, with 1,500 miles, does this - exactly. Dealer gave me the same answer. Do you have any additional photos of how you accessed this flap?

 

[Shumax]

2024 badlands. Started the day I picked it up. Very annoying. Took it to the dealer and they gave me the run around on the service notice - even though it clearly says 2021-2023 and mine is a 2024.

I pulled the vents on both sides and added doubled sided foam tape to the flaps. It adds enough weight that they won’t flap around as easy. No issues up to 80mph, now.

 

[sajohnson]

Excellent photos Shumax!

How are the extractors located/removed? Can they be accessed by removing interior panels? It looks like that's the case.

I'm asking because we've had trouble with mice getting into our Badlands and I read somewhere that if a flap(s) gets stuck open they can get in that way.

 

[sajohnson]

I found an answer to my question about how to access the extractors/pressure relief vents:

"For a 2022 Bronco Sport, the cabin air pressure vents are located behind the rear bumper cover, at the lower back corners of the vehicle
. Accessing them requires partially or fully removing the rear bumper.
The cabin pressure relief vents consist of a plastic grille and rubber flaps that allow air to exit the vehicle when you close a door or operate the climate control system. This prevents damage to the door and body seals.

How to access the cabin air pressure vents
Disclaimer: This is an advanced procedure that requires automotive knowledge and tools. If you are not comfortable performing this yourself, it is best to take your vehicle to a professional. Improper removal could result in damage to the bumper cover, paint, or wiring harnesses.
What you will need

Socket wrench and extension set (metric, likely 13mm, 18mm, and 19mm)
Trim or body clip removal tool
Flathead screwdriver
Helper (recommended)
Drop cloth or blanket to protect the bumper

Step-by-step instructions

Open the rear liftgate to get access to the work area.
Locate the hardware: The rear bumper is held on by several bolts and clips. On a 2022 Bronco Sport, you will typically find:
One 13mm bolt in the wheel well on each side, holding the bumper fascia to the body.
Multiple bolts underneath the vehicle, behind the bumper, attaching it to the frame.
Disconnect electrical components as needed. Before you pull the bumper away, you will need to disconnect any wiring for the rear license plate lights and rear parking sensors (if equipped). The harnesses are located on the passenger and driver sides behind the bumper.
Remove the bumper cover. With all fasteners and wires disconnected, you and your helper can now carefully remove the bumper.
Access the vents. Once the bumper is removed, you will see the black plastic pressure relief vents on the lower back corners of the vehicle body. They are typically held in place with clips and can be popped out with a trim tool.

How to check for proper function
If you are troubleshooting an issue, you can perform a quick check without removing the bumper.

Close all the doors except for one, leaving it latched halfway.
Stand near the back corner of your Bronco Sport, listening near the bumper cover.
Have a second person push the open door firmly shut.
If the pressure vents are working correctly, you should hear a "whoosh" of air escaping, followed by the sound of the vent flaps closing. If you don't hear anything, the vent may be stuck or malfunctioning."

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[Dude]

@sajohnson are you going to do all that?

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