'21 BS Outerbanks, Fan rattling sound on D(rive)

NewStockyBalboa

Outer Banks
Well-Known Member
First Name
Hav
Joined
Nov 16, 2023
Threads
8
Messages
45
Reaction score
21
Location
USA
Vehicle(s)
2021 Ford Bronco Sport
Hello everyone,

I’m having an issue with my 2021 Bronco Sport Outer Banks (about 80k miles).
When the vehicle is in Drive and stopped at a red light, I hear a rattling noise at idle or under ~2,000 RPM. The sound seems to be coming from the front of the vehicle, possibly the radiator / cooling fan area.

The noise goes away as soon as I start accelerating and only happens while stopped in Drive. It does not occur in Park or while driving.

Has anyone experienced something similar or have ideas on what to check?
Thanks in advance.
Sponsored

 

incavulator

Badlands
Well-Known Member
Joined
Aug 5, 2025
Threads
0
Messages
164
Reaction score
367
Location
USA
Vehicle(s)
2021 Bronco Sport
Sounds like perhaps an exhaust heat shield where the weld has come loose. I have not had this problem on my BS, but have had it on several other Ford products. You'd really have to (CAREFULLY and SAFELY!) have someone look under it while this is happening to find the source. This is best done on a hoist with all wheels off the ground.
 

thomasm23

Outer Banks
Well-Known Member
First Name
Tom
Joined
Jun 7, 2021
Threads
34
Messages
792
Reaction score
914
Location
Los Angeles Metro
Vehicle(s)
2021 Bronco Sport
Hello everyone,

I’m having an issue with my 2021 Bronco Sport Outer Banks (about 80k miles).
When the vehicle is in Drive and stopped at a red light, I hear a rattling noise at idle or under ~2,000 RPM. The sound seems to be coming from the front of the vehicle, possibly the radiator / cooling fan area.

The noise goes away as soon as I start accelerating and only happens while stopped in Drive. It does not occur in Park or while driving.

Has anyone experienced something similar or have ideas on what to check?
Thanks in advance.
Check the air box for a rattle. The 3 rubber grommets that retain the air box are known to come out and become missing.
 

thewolfpup

Outer Banks
New Member
First Name
Mark
Joined
Nov 11, 2025
Threads
0
Messages
4
Reaction score
8
Location
Reading Pa
Vehicle(s)
Ford Bronco Sport
Yes, I had the same thing. I agree it is the air intake box. I put a cold air intake on mine and put a grommet in the front hole to stop it from vibrating and that all goes away then.
 


OP
OP

NewStockyBalboa

Outer Banks
Well-Known Member
First Name
Hav
Joined
Nov 16, 2023
Threads
8
Messages
45
Reaction score
21
Location
USA
Vehicle(s)
2021 Ford Bronco Sport
Check the air box for a rattle. The 3 rubber grommets that retain the air box are known to come out and become missing.
I do have an update, and apologies for the delay. You are right, this was the issue. They replaced three insulator assemblies (grommets). The part number is CC1Z-99B929-A. The charge was $16.40/each.

Noise completely gone. But they charged me $316.43 for labor. Total out the door for this was $365.63.

Thank you to this sub again. Appreciate the help and support.
 

thewolfpup

Outer Banks
New Member
First Name
Mark
Joined
Nov 11, 2025
Threads
0
Messages
4
Reaction score
8
Location
Reading Pa
Vehicle(s)
Ford Bronco Sport
WOW
I REPLACED MY GROMMETS WITH ONE I MADE OUT OF A GROMMET FROM MY SPARE PARTS,
IT COST ME NOTHING
Sponsored

 
 







Top