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The MINI with neverending issues... (2008 Cooper S w/ dealer-installed JCW kit [chip tune, bigger intake, bigger exhaust])

Recently I've noticed a whirring or whistling noise above 30mph. It does not happen under that speed (or at least is inaudible), and the pitch of the noise does not change with vehicle speed or engine speed. It also does not change if I turn left or right, so it doesn't seem to be suspension-related.

Any ideas? If I had to guess, I'd say it was coming from somewhere close to the firewall near the center, but it's very hard to pinpoint.

Car performance is unchanged, no CEL.

Update: The noise is definitely coming from under the hood in front of the driver seat. It gets louder the faster I go, but does not change in pitch. It does not appear to be related to suspension or tires, as sharp turns at speed do not affect it. Here is a photo of under-the-hood http://www.eurocarnews.com/media/pictorials/1654/8417.jpg There's not a whole lot there...

Update 2 I realized what the noise reminds me of. It sounds like air blowing over the top of a straw. A really breathy whistle.

Update 3 More troubleshooting steps: I've shifted into neutral and let the engine come down to idle and the noise is unchanged. I've tried activating the windshield wipers, no change. I've brought the engine to 2k rpm while not moving, and the noise does not occur. I've driven with my head out the window and cannot hear the noise over the wind.

Update 4 It may be imagination, but it might be getting louder?

Things I've noticed: 1. The noise GOES AWAY when I turn the steering wheel in either direction. The power steering pump in this car is electric, not belt driven. 2. It is much louder at highway speeds, but is noticeable even under 30mph (just very quiet). The noise disappears under 5-10mph.

I put the car up on ramps and gave everything a good lookover. Aside from dirty oil residue all over the transmission (I'll have to track down where that leak is coming from...probably the filter housing), everything is in good shape. One of the accessory pulleys is a bit squeaky. I couldn't tell if the squeak was from the alternator or the water pump (they're right next to each other).

I didn't see anything that looked out of place and nothing was loose.

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  • Sure you're not hearing the turbo? (I forget which year they switched from a supercharger to a turbo) – 3Dave Sep 12 '17 at 13:29
  • Yep, definitely not turbo whine. – Spivonious Sep 12 '17 at 15:12
  • whirring/whistling as in maybe the wind catching something and wipping it around (weatherstripping/tape/fabric/etc)? – s1ns3nt Sep 12 '17 at 15:43
  • Have you done a visual inspection under the car? Is there anything rubbing the tires? Are tubes or pipes touching the undercarriage? – CharlieRB Sep 12 '17 at 20:02
  • I should have some time tonight to get it up on ramps. – Spivonious Sep 13 '17 at 13:04
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Just spit balling here as it's hard to determine the issue without actually seeing the car / hearing the "whistle". Anyways, have you got an aftermarket manifold installed / messed around with the manifold recently? It could be air leaking from the manifold causing the whistling noise. If this is the case try changing the gaskets, make sure you buy some thicker ones and seal them up properly with gasket sealant or worse case scenario you have a warped manifold which is causing air to leak out.

I would get it checked out at the garage over the weekend. Good luck!

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  • No, nothing changed recently. The last work done was to replace a failing high-pressure fuel pump back in June. The whistling noise started last week. It also only happens at speed...I'd think a manifold leak would whistle constantly, no? – Spivonious Sep 13 '17 at 14:32
  • I've had this issue on an MR2 before and the manifold leaks are not always constant depending on the size of your leak. As you go faster more exhaust fumes would be pushed out from the engine through the manifold and some may escape through a gap in the gaskets after a certain speed if they're not installed properly / getting a bit old. I should have asked this earlier. Does the noise stop if you let go of the gas pedal and let the car coast at 30mph+? If it does not stop and is continuous then it's definitely not the manifold. – guest Sep 13 '17 at 14:58
  • The noise continues even if I shift to neutral and let the engine come down to idle. It's completely dependent on vehicle speed. – Spivonious Sep 13 '17 at 15:08
  • I see, then the issue shouldn't be the manifold unless you have an absolutely huge leak but by then your whole engine would sound like a tractor lol. There are a lot of possible issues with "whistling" noises, I still think it's best getting it checked out asap just in case it's one of those issues and it becomes unfixable / very pricey the longer you leave it. Fingers crossed its nothing big! – guest Sep 13 '17 at 15:18
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Hard to say without hearing the sound, but you did rule out an engine problem, so have you gone over a bump really hard or hit something under our car since last week? It could be a part rubbing up on another in the suspension work/drivetrain since it only started last week I think this is likely the cause! It would be nice to hear the sound though, this is only a guess!

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  • I don't remember hitting anything especially hard. The suspension is so tight that even small bumps are jarring. I'll try to get a recording of the sound. – Spivonious Sep 15 '17 at 20:16
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Troubleshoot - Keep the car in idle state, pull up hand brake, put gear to neutral and accelerate If you hear the same sound, then it should be from the engine or parts connected to engine like turbo, radiator fan etc.

If not, then it should be the problem of suspension, bearings or tyres.

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  • It's definitely not engine-related. The sound does not occur unless the vehicle is traveling 30mph or faster. – Spivonious Sep 15 '17 at 20:14
  • It should be with the engine belt, spray some talc power/vegetable oil under the engine belt.. see if the problem goes away.. – Mudassir Hussain Sep 15 '17 at 20:29
  • It's not belt noise. The noise is coming from in front of the driver's seat, which is on the opposite side of the engine bay from any accessory belts. – Spivonious Sep 15 '17 at 20:34
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After getting a few second opinions and jacking up the car and spinning the wheels, I'm forced to conclude that it is simply tire noise. The fronts are getting to the wear bars and apparently like to whistle over 30mph.

It was a bad wheel bearing! The whistling eventually gained a grinding noise. After replacing the worn out tires, the noises continued. I took it into the shop and the tech diagnosed a bad bearing on the front left (although he could only hear it was the wheel was nice and warmed up).

Bearing replaced and the car is back to being silent!

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