anyone had a whistle noise on cold acceleration -? Cooper

[BartMack]

In the morning when I leave for work for about 2 blocks my Cooper makes a variable but high pitched whistle when accelerating... it was just in for service and my dealer says they have never heard of such a thing and have no idea what it could be.

To me it sounds like an air intake type of noise from the engine. It just fades out after a minute or two- but it is loud. The 'variableness' relates directly to rpms, higher rpms=higher pitch whistle.

[Paul]

Can you be more descriptive?

[BartMack]

well, ok.. it was a sunny day, it was clear and cold. The neighborhood children were waiting for the school bus with their parents standing nearby. All I could find on the radio was stupid dj chatter... I did notice that a neighbor I had seen chopping wood in his front yard had gotten quite a bit done. And my new neighbors across the street had put out what must be a 20 foot long row of empty boxes and packing materials....

[BartMack]

sorry Paul, I just couldn't resist...

[cristo]

I've noticed the same thing. When the temp is less than 25-30 degrees F, I get a
whistle between 2500 and 3500 rpm just after startup for a few blocks, then it goes
away. I'm guessing it's the serpentine belt tensioner bearing or the alternator or
something similar from the sound of it. I'm going to mention it to the dealer when
it goes in for the first oil change in about a month. Anyone else???

[BartMack]

Cristo, thank you for responding! It's just really helpful to hear somebody else has a similar issue..
It's been in the 30s (F) here, and I've heard it 2 times today, first thing in the morning & again leaving work.

The second time I noticed it I was backing up, so it happens regardless of direction, but much less noticeable on the back up.

It seems to be coming from the central front area of the car.

[cristo]

actually, my noise does vary directly with rpms....starts above 2500 and goes up in pitch
until before 3500 when it fades and dissapears. also, I can reproduce it by revving at a standstill
in neutral or while moving. sounds like vhrrrr (kind of like when you
whistle and hum at the same time). Haven't been able to get someone out to listen while
the pedal is depressed yet to localize it, and it dissapears after minimal warming up, so
extended tests aren't possible.

[Paul]

I meant what kind of whistle. Cheeky blighter.

[BartMack]

Quote: Originally Posted by cristo

actually, my noise does vary directly with rpms....starts above 2500 and goes up in pitch
until before 3500 when it fades and dissapears. also, I can reproduce it by revving at a standstill
in neutral or while moving. sounds like vhrrrr (kind of like when you
whistle and hum at the same time). Haven't been able to get someone out to listen while
the pedal is depressed yet to localize it, and it dissapears after minimal warming up, so
extended tests aren't possible.

I tried revving it in the driveway and it did it at a standstill (right between 2500 and 3500 like you said) I had earlier thought that it was related to the motion of the car, but apparently not..

[cristo]

I'm noticing this more this winter.
It's a sharp whistle ("vrreee"... raises in pitch as the rev's increase)
when revving the car (still or moving) from about 2-2.5K, and then
again from 3.5-4K (although the pitch is in the same range for both rpm ranges).
I initially thought it might be a bearing (idle tensioner, alternator, etc.), but now, I'm
thinking it may be a valve in the vacuum system that isn't fully closed when it's
really cold out. It goes away quickly when the car warms up, and I don't often have
a ready accomplice to work the gas pedal to localize it.
Anyone else have this or figure it out? I'm guessing the fuel tank vent valve or
something similar so far.

[Chilipeppa03]

I have the same problem with my Cooper. Very strange problem!!!

[Cooper76]

It's the MINI version of WOOOOHOOOOOOOO!!!!, or his excitement of getting out for another drive.

My BMW had a short whistling sound on some mornings, usually cold ones, when I would first drive off, then it would disappear. So, I am suspecting it is not a defect or fault.

[NTHUSIAST]

I have a similar sound, and after some investigating, I think I have successfully traced it.

When I start the car (04 MCS) and it has been sitting in the cold (seems like anything below about 40 degrees), I get the same whistling/squeaking sound when I rev the engine. The whistle/squeak appear when reving up or when blipping the throttle and then releasing.

I traced my sound to a slipping supercharger belt. For whatever reason, when the engine is first started and cold, the belt slips if you rev the engine. As soon as the engine begins to warm up, the slippage goes away. I attributte this to not only cold weather, but also my 15% ALTA reduction pulley and its install.

Since the pulley is 15% smaller in diameter it does create aditional slack in the belt. But the stock belt tensioner is more than capable of picking up this slack (unless you get a 19% reduction pulley, but that is a whole different can of worms). Where I think my real problem came in is that we used some lubricating spray (graphite based) while removing the pulley (it was stuck on there good!), and I think the lubricant is still causing a little slippage of the belt until it gets warm.

My proof of this came after I took the time to use a de-greasing product a few weeks ago - applied, let it sit and then rinsed thoroughly. The squeak went away for a few weeks but has slowly started to return. I am hoping to do another round of de-greasing later this week. Hopefully this will take care of it for good.

Anyway, hope this helps!

[BartMack]

no, it can't be the supercharger belt , because I had the whistle on my 03 MC (no supercharger).
It only happened on cold mornings for the first 2 -3 minutes until the engine warmed up.

I also had belt screech which would happen later in the day on startup, like when I was going to lunch or going home.

Additionally, I had a third symptom- periodic rough idle drop to the point of shuddering, which could happen at any time, but almost always happened onthe first take off on a cold start.

I had it in 2-3 times for these, but never a solution, then I traded for an 05 S.

[BartMack]

Quote: Originally Posted by cristo

I'm noticing this more this winter.
It's a sharp whistle ("vrreee"... raises in pitch as the rev's increase)
when revving the car (still or moving) from about 2-2.5K, and then
again from 3.5-4K (although the pitch is in the same range for both rpm ranges).
I initially thought it might be a bearing (idle tensioner, alternator, etc.), but now, I'm
thinking it may be a valve in the vacuum system that isn't fully closed when it's
really cold out. It goes away quickly when the car warms up, and I don't often have
a ready accomplice to work the gas pedal to localize it.
Anyone else have this or figure it out? I'm guessing the fuel tank vent valve or
something similar so far.

yeah I agree, I always thought it sounded like a vacuum system valve too, but the MINI techs told me there was not any intake valve to even make such a noise... but then I've discovered they don't ever really listen to me anyway, so who knows