Recently switched out my aging front base bumper for a freshly resprayed Cooper S front bumper. Really like the look a lot!

As an aside, if you decide to do this and happen to run across this post, you may have to:

1. Move the fog lights to the alternate position
2. Cut part of the aluminum bumper support so the turn signals will clear it. They are spaced wider out on the Cooper S bumper.

At any rate, on to the purpose of this post...I'm now getting a whistling sound around 60mph and above that is definitely wind related. Any Cooper S owners ever get a whistling noise from their front bumper?


EDIT/UPDATE: The cause was a poorly seated and partially broken seal where the steering column passes through the firewall. The noise was not in any way related to the bumper swap, just a coincidence it happened around the same time.

 

There is a past thread on something as this. Need to do some digging

 

This is not the thread but does have some comments. I think what I am thinking about had a video involved, but I see so many threads . . . . .


https://www.northamericanmotoring.co...-at-speed.html

 

Thanks! I ran across a few threads mentioning wind noise, but haven't seen anything about the front bumper being the cause. In my case, I'm pretty sure that's what causing it, since I just switched it out and the noise changes when I'm following a car vs. not.

I was looking at the bumper cover and noticed someone at some point someone drilled 1/4" holes on the tops of the black trim pieces. It could be those acting like a whistle with enough wind going over them. I'll try covering them with some tape to see if its the fix.

I also noticed they trimmed the little lip at the top of the bumper in a few spots. I doubt that could be causing it, but maybe, it acts to deflect the air in some way to prevent whistling.

Will try a few things and report back if I solve it...

 

An update on this - I noticed today that if I switch to recirculate mode, the noise was drastically reduced, but still there.

My theory is the recirculate flap is acting as a baffle, preventing the noise reaching the cabin through the duct work. It does mean the noise might be coming from around the fresh cabin air intake though. It is not the blower fan itself, since the noise goes away when the car is stopped. Interestingly, the noise gets louder at cruising speed and with the blower motor at higher speeds - again pointing to issue around the fresh air intake area.

I guess its possible the Cooper S front bumper, with the larger bottom grille, is letting more air into the engine bay, and this increased air flow is finding its way to somewhere near the ductwork.

I've run across a lot of posts of people mentioning a similar problem, but there doesn't seem to be a single solution.

I'll keep troubleshooting this and report back if I solve it.

In the meantime, if anyone has any suggestions, let me know!

 

Have you compared the backsides of both bumpers? Maybe there is something missing or an extra hole for something.

 

I compared them and did a lot more troubleshooting over the weekend. Still haven't been able to find the cause.

I put masking tape in various spots all over the bumper, none of which made the noise disappear. Putting masking tape across the upper chrome grill did however make the noise worse. But putting tape between the crack of the hood and bumper didn't change anything. It seems that taping that grill is forcing the air more over whatever is whistling, but its incredibly difficult to pinpoint it.

Also tried trimming the bottom air dam in the middle to match the base bumper's shape. It is shorter for the middle section. No change. I do like the look better though - along with matching base coopers, it also matches the newer MINIs a little better, which only have the air dam in front of the front wheels.

I searched through all the threads on the issue. For a whistle with the recirc off, but not on, the only solution I found was a cabin filter put in incorrectly. I tried taking my filter completely out, but there was no change. I'll have to try taking the cover completely off with no filter and see if there's a change.

I even tried driving with the bumper off - and...the whistle went away! The problem is I don't know if it's that actual bumper that's whistling or if the bumper is forcing air to some other location that is whistling. Based on how the recirc plays into this, I tend to think its the second.

Other work I did on the car around the same: swapped brakes, but it's not a brake sound. I thought it might be the drilled rotors, but why would taking the bumper off change that? I also did some wiring under the dash for headlight washers, so its certainly possible I knocked a tube or seal just loose enough to cause a whistle, but you would think I still hear it with the recirc on if the blower speed was high enough.

This one is turning out to be pretty elusive, but I'm not throwing in the towel yet...will keep testing and looking for it as I have time!

 

What year "S" Bumper are you using on your '03 Cooper. Not sure if that could even have anything to do with it. I used an '06 on my '06 Just-a cabrio with no whistle and did not have to make any modifications to the alum bumper brace to fit it...

 

I looked into this back when I was putting the "S" cover on. The "S" bumper cover never changed, but for earlier years that aluminum support was different between the base and S models. Not really sure why they made it that way since now if you have to buy a new one, its the same part for both base and S models between all the first-gen years.

Here are the parts I had to trim wider to make the blinker housings fit in. Not really sure how air could even be getting into that area behind the cover.

 

Did the S bumper fit with the base front fender trims? I have been looking for a Chili Red front bumper for my '06 Justa daily driver since the original got damaged by a member of NW Ohio's wildlife viciously attacking my MINI!

 

The fender trim on the hood is the same and matches up with no problems. The black trim on the bumper itself is different between the base and S, so try to get one with all the trim included.

Since you have an '06 with the facelift front bumper cover, you probably don't have to trim the aluminum support like I did, and you might not even have to move the fog lights.

 

Awesome. Thank you, and good luck isolating the cause of the whistle.

 

After some more troubleshooting, I'm pretty sure this problem is not actually due to the bumper swap.

I found that I could hear a very quiet whistle when stopped, but it went away when I opened a window or turned the air to re-circulate. I think this is the whistle that gets much louder when going down the highway.

It seems to show up when the interior air pressure is "pushing" air back out through a hole somewhere.

I ran a wire through the large firewall grommet next to the brake booster for the headlight washer around the same time I switched bumpers, so I tried re-taping that, but there was no change. I think the problem is somewhere in the firewall - a missing or mis-aligned grommet or something similar. I'll keep searching...

 

Had some time today to do some more searching. I managed to get myself in the driver's footwell with all the doors closed and the cabin fan running and started pressing on the grommets in the firewall. I pretty quickly found the one that changed the sound: the steering column one!

The rubber column cup boot has two white plastic rings that snap together over a white plastic piece on the column itself to hold a rubber cup in place. This creates a seal that still allows the column to spin.

In mine, the lower white plastic ring is missing, causing there to be a gap between the column and the plastic rings that is still there (see picture). When I pressed this down, the soft whistle sound went away.

The subframe has been down a few times over the years, and my guess is that ring was lost one of those times due the steering knuckle bolt not being loosened. The fact that the whistle seemed to show up after the bumper swap appears to be a coincidence.

Unfortunately, the plastic rings seem to only come with the steering column and not separately. I'm going to try to stop by a local salvage yard tomorrow to pickup a used column and give it a try. It seems very promising.

 

I was able to get a good used lower column with all the rings and seals where they should be and after installing all is solved!

I'm actually impressed with how much quieter everything is now. I think there was a lot of road and engine noise making its way through that missing steering column piece. And the whistle is completely gone.