odd "whistle" "squeel" while driving?

So i was driving around with my windows down for the first time, and noticed an odd whine, whistle, squeel...

It's very quiet, and I only hear it when I'm about 1/4 -1/3 throttle.
I cant pin point the noise, but I hear it when I shift, and when im driving and tap the gas the right way... Sounds like maybe from.the rear? Again not positive.

Bump, it's really annoying, and I've never heard it before in any car.
when I'm in 5th, I notice the noise when the MPG gauge is between 21-25mpg.

Ccv...

Also check for cracks in you intake boots

Originally Posted by dopey88

Also check for cracks in your intake boots

This. Mine had cracks. Fixed it. Runs a lot smoother now. I had to reset my adaptations afterwards, though.

Could it be the fact I have a small hole in my air box?
I did the custom airbox mod thing, the edge cracked, and I was too lazy to seal it.

It just to me, sounds more of a metal whistle, than air.

It's a screechy whistle, so I see how that could sound metallic... There are some videos on youtube of people trying to diagnose this issue, so maybe you can find one that confirms the sound for you.

It is possibly your intake hoses or one of the hoses to the CCV.

Yes it does sound metallic.. Not like an air whistle, as I would ASSUME if it were an air whistle, it'd be louder the higher RPM.

I'll check some youtube videos. I tried taking a few, but I think it was a bit too windy... lol

I hope it's not the CCV, I saw a few DIY's, and it looks like a BITCH to replace..

If it's only when the throttle is partially pressed, it could very well be your TB. As-in nothing is wrong. If you put on an aftermarket intake, this is the "intake whistle" that people talk about. The intakes do NOT give you the whistle, they DO remove the BMW baffling that hides most of it. Even putting in a drop-in filter is enough to reveal it. Some E46s do it more than others. I noticed that at lower elevations my car whistled less so air density MIGHT have something to do with it. If you shut the engine off and listen carefully very soon after shutting it off, do you hear a clink/ka-chink/metallic sound? Does it sound similar? If it's just your TB whistling then it should have a similar sound quality to it.

The CCV is indeed a nightmare. When your engine is idling, pull the dipstick out. Is Chewbacca hiding in your engine? If no, your CCV is probably fine for now. Also the CCV usually fails in the cold, not the early summer.

I spent two months chasing that whistle. Even did a 10PSI smoke test. Nada. Sealed tighter than a pickle jar. Then I read a post from waaaaay back when the E46 was new of people complaining about the whistle and it was normal.

Here's a video I did of the Injen intake noise since someone requested it. Listen very closely starting at 6 seconds right as the engine begins to rev. Do you hear your whistle?

YES that's like the noise I hear! It's somewhat metallic. I HATE it.
That's the exact noise.

I've never noticed it before, (never really drove with windows down until recently)

But I do have a K&N drop in filter, and I did mod my airbox, with a 3" pipe going down to the bump scooping in the air.

The last set of revs in the video, demonstrate the whistle noise I hear perfectly.


Now.. As it's the most annoying noise ever, because while driving, to keep a constant speed, where the pedal rests, the noise is created.

And is there any way to fix this?
Because the noise is killing me. lol

TB = throttle body.

Curing it? Use a paper filter and re-seal your airbox. Or just get used to it.

It's just a sound the car makes. Not much you can do about it.

ETA: I just got used to it. I LOATHED it at first. All new pulleys, intake books, DISA o-ring, IAT O-ring, SAP lines.

But then I realized I had to accept it into my life and just accelerate a bit more. This had a side-effect of keeping my Injen right in the part of the revs where it sounded burbly/growly just before it starts to roar. My mileage suffered, but my ears benefited.

I'll re seal the air box a bit soon.

As for the curing it, I'll have to search the forums, but is the TB easy to remove to clean, (or replace considering I have a brand new one sitting in my brothers room in the package)

((I'm 18. Got a BMW. My older brothers friend is a lead mechanic at Sterling BMW, gave my brother some parts to sell to me when needed.. Parts that commonly go on the E46.))

Also, I've seen TB spacers, which claim to add more power on TurnerMotorsport.com.... any ideas? Would it be worth getting? They claim an extra 10hp.

Originally Posted by mattfarrington

I'll re seal the air box a bit soon.

As for the curing it, I'll have to search the forums, but is the TB easy to remove to clean, (or replace considering I have a brand new one sitting in my brothers room in the package)

((I'm 18. Got a BMW. My older brothers friend is a lead mechanic at Sterling BMW, gave my brother some parts to sell to me when needed.. Parts that commonly go on the E46.))

Also, I've seen TB spacers, which claim to add more power on TurnerMotorsport.com.... any ideas? Would it be worth getting? They claim an extra 10hp.

TB isn't bad to replace as long as you have a decent socket set with extensions and some patience. Just keep removing hoses starting from the airbox back. There's a very real probability that a new TB will make the same noise since it's the harmonics of the shape, hence why BMW made ribbed soft rubber hoses and pointed all airbox intake points forward and used thick, softish plastics with air between layers.

There's a very real chance you will hear this noise no matter what. Enjoy the car for what it is and try to stop thinking about it. Once you know what to listen for, you hear it in almost every E46.

Well, as long as it's not bad. It's alright. I was worried it was like a bad bearing or something.

Here is a video of what I am experiencing. Any feedback is appreciated:

I'm only saying what I've heard in the past. but Maybe the fan needs to be replaced?
Sounds like a bad bearing. And when the car warms up, the fluid does, so it doesn't squeal?


My car just whines on idle. I think it's due to one of the pulleys missing a little chunk. gotta get that fixed.

I think deadwood83 is correct, the sound you are hearing is coming form your throttle body. The cause is modifying your intake. Your factory airbox is designed to cancel this frequency out but installing a CAI intake or modifying your airbox will allow this noise to escape. I noticed the same noise on my car the minute I installed my first CAI, it was a AFE intake with the metal cover on top. Then I went to the Conforti intake which wasn't as loud but still has a noticeable whistle to it.

i did no modifications. just put a k & n filter instead of factory filter.

guess I should have watched your video, duh. Does the noise go away if you open your oil cap with the engine running? If it goes away I would say it's your crankcase vent valve, if not it sounds like it could be a belt pulley.