Help me diagnose the cause of this high pitch whine

pwnsweet · Post by **pwnsweet** » Wed Nov 21, 2018 2:46 am

Thanks in advance for reading/helping.

This will be long so I'll get straight to it. My '03 E85 3.0i has a high frequency "whine" sound that presents around 1600-2000rpm (detailed testing info below). I do not exaggerate when I say that it drives me absolutely insane and I will sell the car if I can't find and fix the problem. It's been there since I bought it (9 months ago) and it's the type of high frequency sound that aging people stop being able to hear as the frequency range of sound that their ears can hear begins to narrow.

To put it another way, it sounds exactly like "coil whine" from a computer component under load/stress. Another way to describe it would be the high frequency "static noise" from a speaker that's turned on to full volume but isn't playing any music. Hopefully you now have an idea of the type of sound I'm talking about.

Some observations:
1. Only seems to happen during throttle/acceleration. ie, going from 1600rpm up to 2000rpm. Doesn't happen on the way down (no throttle, 2000rpm down to 1600rpm)
2. Only occurs when car is in gear (no sound when revving in neutral at standstill or moving at 70km/h)
3. Occurs in all gears (including reverse)
4. Very, very slow/light throttle from 1600rpm up to 2000rpm results in the sound being very faint/unnoticeable. In contrast, heavy/full throttle in the same rev range results in the sound being most obvious. This implies the sound "intensity" is related to engine load
5. The sound appears to be coming from the front of the car. This was determined by the fact that the sound is easier to hear when the foam pieces (both) are removed from the sound generator, and harder to hear when the foam is in place. (For the uninformed, the "sound generator" pipes the engine sound into the cabin through a tube. This tube has 2 foam pieces, one at each end of the tube, to dampen the engine noise)

Things I've tried to fix it:
1. The local mechanic thought it was the water pump. He replaced the pump and thermostat but, notably, not the belt or tensioner bearing.
2. I checked the air intake boot and all associated tubing for cracks. A very, very small crack was found and plugged

Details about the car:
1. 85000km
2. Automatic
3. M54B30 engine

patriot66 · Post by **patriot66** » Wed Nov 21, 2018 9:14 am

Sounds like an air leak to me. I've had several and eventually replaced all the CCV and several gaskets etc to cure it

road warrior · Post by **road warrior** » Wed Nov 21, 2018 9:43 am

I had a whine in my car for while, but she went shopping so it's OK now

rally-chris · Post by **rally-chris** » Wed Nov 21, 2018 3:48 pm

Leaking swirl flaps in the inlet manifold?

inject · Post by **inject** » Wed Apr 24, 2019 7:29 pm

Cooling Fan can whine.

greg81 · Post by **greg81** » Wed Apr 24, 2019 7:33 pm

road warrior wrote: ↑Wed Nov 21, 2018 9:43 am.I had a whine in my car for while, but she went shopping so it's OK now

rally-chris wrote: ↑Wed Nov 21, 2018 3:48 pm Leaking swirl flaps

Linked issues?

Phoenixboy · Post by **Phoenixboy** » Wed Apr 24, 2019 7:37 pm

greg81 wrote: ↑Wed Apr 24, 2019 7:33 pm
road warrior wrote: ↑Wed Nov 21, 2018 9:43 am.I had a whine in my car for while, but she went shopping so it's OK now
rally-chris wrote: ↑Wed Nov 21, 2018 3:48 pm Leaking swirl flaps
Linked issues?

road warrior · Post by **road warrior** » Wed Apr 24, 2019 7:39 pm

greg81 wrote: ↑Wed Apr 24, 2019 7:33 pm
road warrior wrote: ↑Wed Nov 21, 2018 9:43 am.I had a whine in my car for while, but she went shopping so it's OK now
rally-chris wrote: ↑Wed Nov 21, 2018 3:48 pm Leaking swirl flaps

Linked issues?

are you saying my wife has leaky flaps ? if so, i aint gonna be the one to tell her....

greg81 · Post by **greg81** » Wed Apr 24, 2019 7:41 pm

road warrior wrote: ↑Wed Apr 24, 2019 7:39 pm
greg81 wrote: ↑Wed Apr 24, 2019 7:33 pm
road warrior wrote: ↑Wed Nov 21, 2018 9:43 am.I had a whine in my car for while, but she went shopping so it's OK now
rally-chris wrote: ↑Wed Nov 21, 2018 3:48 pm Leaking swirl flaps

Linked issues?
are you saying my wife has leaky flaps ?

Not at all.

ph001 · Post by **ph001** » Thu Apr 25, 2019 11:25 am

You would have to suspect a bearing or something on the auxiliary serpentine belt so the first thing I would do is remove that (or at least take the tension off it by locking the auto-tensioner so that it doesn't spin). If that makes no difference, might sound weird, but try replacing the oil filter. Seen some very strange noises come from there in the past when the o-ring degrades on the filter element.

bearded_ed · Post by **bearded_ed** » Sat Jun 06, 2020 10:48 pm

I hate resurrect a post but this literally exactly what I'm struggling with! Only difference being mine is manual with 92k miles...

Any thoughts on what it could be?!

ph001 · Post by **ph001** » Sun Jun 07, 2020 10:59 am

Does it sound like this?...
https://youtu.be/0SK23DgAq2A

BumpyZ4 · Post by **BumpyZ4** » Sun Jun 07, 2020 6:08 pm

Believe it or not it is the engine oil filter. Replace your oil filter with a Mann filter and the noise will go away.

bearded_ed · Post by **bearded_ed** » Sun Jun 07, 2020 10:08 pm

ph001 wrote: ↑Sun Jun 07, 2020 10:59 am Does it sound like this?...
https://youtu.be/0SK23DgAq2A

Not even a little bit! I also just changed the filter about 2 weeks ago.
Noise was there before this too. Thanks though.

ph001 · Post by **ph001** » Sun Jun 07, 2020 10:21 pm

Can you record it on your phone and put it on YouTube?

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