Hello all, I just picked up a new to me R56 and after prior research I figured I'd be doing a little tinkering here and there. If I gradually roll on throttle there is no issue all the way to redline, but if I stab it at about 4k RPMs a loud whistle sound comes from the rear. It does not happen while stationary, only under load. It's a 2010 S MT with 55k mi. Crate motor from BMW installed about 2k ago because of timing chain damage (have receipt from May). PO was a "certified mechanic" and did the swap. Said belt was replaced, and it doesn't sound like it's coming from the engine bay. No CEL or any other issues. Magnaflow catback is the only mod. Looks like he did a pretty quality job. Wouldn't be able to tell if it weren't for the shiny engine. I consider myself to be fairly mechanically inclined, where should I begin looking?

 

Starting here might help.
https://www.northamericanmotoring.com/forums/search.php

 

Thank you, I am familiar with the search function, but the only thread with similar circumstances I have discovered was this one which was not resolved: https://www.northamericanmotoring.co...tallation.html

I sent him a PM and will see if it was sorted.

 

This is of no help I realize but we had a local club member some years back with basically the same issue. Dealer couldn't find anything wrong and he promptly named his car "The Whistler"

 

Interesting. I know it isn't wind noise related because I can gently roll on throttle and go through all the gears to 100+ mph with no noise at all. Is a loud whistling what a turbo would sound like if it were beginning to fail when producing large amounts of boost? It sounds like someone bolted on an eBay whistle when I punch it.

 

Did you by any chance accelerate fast past a traffic cop? That would explain the whistling sound from behind your Mini! I'm sorry I couldn't help myself, have you checked for holes in the exhaust and or downpipe? Since it's sounding like a whistle it's got to be air blowing through something, what is anyone's guess.

Perhaps it's the noise maker or my previous whistling sound that turned out to be the throwout bearing in the clutch. It sounded exactly like a whistle and was very difficult to pinpoint where the sound actually was coming from because it bounced all over the place being under the car!

Drive your Mini through an empty concrete parking structure, trying not to laugh right now but that might help you out. You might also make a video of the sound because if I am able to hear that highly annoying whistling sound again I'll know whether it's the throwout bearing or a traffic cop, once you've heard it it never leaves your head!

 

I'm sorry but most Mini dealer mechanic's are under trained to perform true "troubleshooring skills", their trained to read codes and replace parts and that's what their good at doing.

Beyond that their clueless which reminds me of the very first timing chain rattling in 2007 when owner's were complaining about the rattling sounds (which they stated was normal, that's what they say when they don't know), no one, not even the engineer's from Mini/BMW could figure it out in time before owner's started blowing engine do to the timing chains coming off both cam sprockets permanently destroying the engines.

You want a Mini mechanic that can troubleshoot your Mini, don't go to the dealers.

 

Under what circumstances were you hearing the throw out bearing? Hopefully that's not the issue, I'll check all the connections from the turbo back once I get it on a rack. I did manage to produce the sound while not under load (Although I hate revving it without being in gear). It really sounds like it's coming from the rear of the car, and video hasn't particularly helped me; I need another set of ears. Thanks for the help.

 

I heard the TOB only when the clutch was engaged, mostly at above 2000 rpm. A Go-Pro mounted to various places under your Mini, you can mount those things almost anywhere. A video is worth a thousand whistles I mean ears.

 

I would have a close look at your compressor blades. You may get some strange noises if one or more have some tip damage.

 

Was the turbo also replaced when the crate engine was installed? If not perhaps wherever happened to the engine could have damage the turbos compressor blades especially if a piece of a valve broke off in a valve/piston strike or even a spark plug electrode that came loose and either piece made it through into the turbos exhaust housing damaging the compressor blades as NB Cooper suspects.

 

This guy went to the dealer because it was a brand new car.. He kept it for about 3 years, drove it everyday and never had an issue with whatever it was...

 

Are we talking about the original owner that owned the MCS that now the OP owns? In any case if the guy you're referring to had the MCS for 3 years and never had a single problem, it makes me wonder why he got rid of it in the first place? If I'm misunderstanding you I apologize.

Anyhow sometimes going to the dealer can cause excessive blood pressure and stress even if it's under warranty because it takes a long time to nail down the problem. I'm also talking about my own experience under warranty, just not the factory one.

No one but me and the OP knows how extremely annoying a whistling sound can be on a turbocharged car, lol!

 

Doubt it's the same car. My friend traded it in a few years ago as he needed something bigger for his business he was starting. Had nothing to do with the car having a whistle.