I just recently had a 17% reduction pulley installed and in the dawn of colder months I've began noticing an interesting whistling noise coming from the engine.

Basically here are the symptoms: any time its below 50 degrees or so there is a distinct whistling noise that becomes audible from about 1500rmps that gets louder as the rpms increase. Once the engine is warm the whistling continues until I gas it up to redline, at which point the whistling stops.

Should I worry about this noise? Or is it a regular side effect of the smaller pulley in combination with cold weather?

 

Did you change the belt with your pulley?
If not it could be slipping belt.
It kind of sounds like a slipping accessory belt on most cars, which becomes noticeable when the temp gets colder.

If you did not change the belt, a new shorter belt could be the fix.

 

Sounds like the belt to me too. My Cooper S has a slipping belt right now, that started a couple of weeks ago as it got colder and wetter out. It's getting changed tomorrow. The sound is different than slipping belts that I've heard before - not as much a squeal, but more a whistle, high pitched. I first thought it was a bearing going bad, but it is definitely the belt.

 

I did have the belt changed BUT the shop showed me that the belt wasn't lined up right. The pulley was out of alignment with everything else... looks like I've gotta expensive supercharger repair to deal with. It is the correct sized belt so if it is still slipping thats bad news bears.

Thanks guys.

*****.

 

Was there a problem before the pulley install?
Is this a shop that knows what they are doing with MINIs?
I know Atlanta is not real close to Knoxville, but before doing anything you might want to make the trip to see Wayland at WayMotorWorks in Atlanta. He will be able to assess the situation much better than most shops.

 

I have a whistle that is barely audible, and only when I press on the gas pedal... I took it in, but the service advisor couldnt hear it, so they didnt do anything about it... The belt isnt slipping. And I have had an RMW tune and the noise is present both before and after... Cant figure it out, doesnt seem to be hurting performance at all, its just there...