Rattling rear noise called a “feature”

[Tomp611]

I have a 22 BSBB w/ 18k miles. Lately I have noticed a rattling noise by the exhaust, as well as water dripping from the exhaust. It is noticeable when starting up and car is idling. Took it to the dealer and they gave me the attached service bulletin and said it’s normal. However the test for this makes no sense. How can you observe it when going 40mph? Anyone else have this issue or experience with this? This sounds like BS…

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[Escape2Bronco]

I have a 22 BSBB w/ 18k miles. Lately I have noticed a rattling noise by the exhaust, as well as water dripping from the exhaust. It is noticeable when starting up and car is idling. Took it to the dealer and they gave me the attached service bulletin and said it’s normal. However the test for this makes no sense. How can you observe it when going 40mph? Anyone else have this issue or experience with this? This sounds like BS…

Water dripping from your exhaust would be considered normal while the vehicle gets to operating temperature. The pressure flaps are there so you can easily close your doors. The issue would be if they are stuck open allowing exhaust gas to enter the vehicle. I’ve never heard mine rattle but under certain wind speeds and vehicle speed and direction, I will hear them “flap” but I wouldn’t call it a rattle and the wind along with the vehicle speed has to be quite high for me to have it happen.

 

[cprcubed]

See this thread, specifically post #27: 2021 Ford Bronco Sport Thumping/Flapping noise | 2021+ Ford Bronco Sport Forum - Broncosportforum.com
Cheers!

 

[Tomp611]

Thank you both for the replies (and link to other thread). This rear noise is something I hear when parked/idle - not a noise I hear when driving. Now I’m wondering if it is something else entirely.

 

[MJbronco]

I've had this rattle in the rear twice now. The first time it was baffling in the muffler, the second time they didn't fully fix and I'm still waiting on them to get it worked out. I believe I'm having the same issue. When you start your car and hear the rattle, try to put some pressure on the muffler and it may deaden or weaken the rattle. That will give you a better idea if it's in the muffler. I believe loose baffling in muffler is semi common issue with the BS

 

[Quashish]

Could also be a part of the heat shielding under the car touching the exhaust somewhere that needs a slight bend the other way. The issue ford gave you a print out of is definitely more of a flapping from wind in the rear hatch area. not a rattle as you describe.

 

[Slingy]

I have a 22 BSBB w/ 18k miles. Lately I have noticed a rattling noise by the exhaust, as well as water dripping from the exhaust. It is noticeable when starting up and car is idling. Took it to the dealer and they gave me the attached service bulletin and said it’s normal. However the test for this makes no sense. How can you observe it when going 40mph? Anyone else have this issue or experience with this? This sounds like BS…

 

[Bill G]

”Rattling” noise in exhaust system at idle could also be cat converter. Filling inside cat could be breaking down and rattling at idle, noise covered by other sounds when driving. Had that problem on a Jeep I had — had to replace cat (not under warranty).

 

[BLUEOVALRACER]

I've had this rattle in the rear twice now. The first time it was baffling in the muffler, the second time they didn't fully fix and I'm still waiting on them to get it worked out. I believe I'm having the same issue. When you start your car and hear the rattle, try to put some pressure on the muffler and it may deaden or weaken the rattle. That will give you a better idea if it's in the muffler. I believe loose baffling in muffler is semi common issue with the BS

I've heard a rattle on mine sometimes when i first start it but it goes away right after it starts

 

[Frosty]

I've had this rattle in the rear twice now. The first time it was baffling in the muffler, the second time they didn't fully fix and I'm still waiting on them to get it worked out. I believe I'm having the same issue. When you start your car and hear the rattle, try to put some pressure on the muffler and it may deaden or weaken the rattle. That will give you a better idea if it's in the muffler. I believe loose baffling in muffler is semi common issue with the BS

Totally agree. Happened to my BSOBX twice! Didn’t take long for the second muffler the Ford dealer installed to also start rattling. Gave up on OEM mufflers & had a unit from Magna Flow installed.
Much cooler sound & no rattles! ?

 

[MJbronco]

I'll look into doing so when I'm not under warranty. But definitely annoying to have it happen multiple times

 

[Tomp611]

I've had this rattle in the rear twice now. The first time it was baffling in the muffler, the second time they didn't fully fix and I'm still waiting on them to get it worked out. I believe I'm having the same issue. When you start your car and hear the rattle, try to put some pressure on the muffler and it may deaden or weaken the rattle. That will give you a better idea if it's in the muffler. I believe loose baffling in muffler is semi common issue with the BS

Thanks! Let me know how it works out for you.

 

[Stircrazy]

I had this, and went for my service a couple days ago. the mechanic owns a bronco sport also and told me exactly what it is. rocks get blowen up between the muffler and the heat shield and caught up between the other heat shield at the back of the muffler and rattle back there.

 

[Tomp611]

I had this, and went for my service a couple days ago. the mechanic owns a bronco sport also and told me exactly what it is. rocks get blowen up between the muffler and the heat shield and caught up between the other heat shield at the back of the muffler and rattle back there.

Very interesting! Did they fix it for you?

 

[Stircrazy]

Very interesting! Did they fix it for you?

no, where we are they gravel the highway frequently, he said when it is nicer and they stop that just to get something in there to scoop it out. I am going to see if I can "adjust" the rear heat shield to make it so they fall out better, but until its nice it can stay.

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