I am hearing a whirring noise (sounds like the HVAC fan) from inside the car on the left side of the car whether the HVAC is on or off.

Additional info:
- 2006 MCS manual
- 85k miles
- installed 15% pulley a week ago along with tensioner, shorter belt and spark plugs
- thought it was the idler pulley, so I changed that and the sound didn’t change
- tried disconnecting power steering pump fan and didn’t change at all
- noise follows the engine revs and is not dependent on vehicle speed
- most noticeable above 2,000 RPM and when holding RPMs consistent, so super charger and exhaust aren’t making much noise
- doesn’t change when applying brakes

Does anyone have any idea what this could be?

 

did you try pushing the clutch in to see if the noise either changes or goes away??

Bryan

 

Oh, your thinking throw out bearing huh?

i will try it with and without the clutch pressed when I get home in a little bit.

 

So no change at all when pushing the clutch in. :(

another thing Ong I checked is turning the AC on the noise seems to be coming from the same area but a different tone than the AC.

it almost sounds like it is coming through the vents

 

Sounds & noises are one of the hardest to find......what you hear coming from say the left front, could actually be coming from the right rear...sound travels through the cars body & frame.

Without actually looking at my two cars for the area that you are describing, I may not be much help.....but.....here is what I would do

Go to Harbor Freight or local auto parts store and buy two items:
(1) Get a mechanic's stethoscope that you put into your ears and it has a long rod on the testing end......
(2) Get about 4-5 feet of 5/8" heater hose

The stethoscope is for testing and finding mechanical noises in the engine, or most any mechanical part, put the ear pieces in, and touch the rod to anything on the car with the exception of the belt & pulleys
The heater hose is for testing air & vacuum leaks....put one end in your ear, and poke around the car and see if you can hear anything close to what you are describing

Now, with all that said....your "whirring" noise could be one of the HVAC door motors inside the heater housing that has either broke, or come loose from the flapper door it operates.....

I know, not much help, but ya gotta start digging deeper, the noise is not gonna jump out at ya saying, "Here I am"

Bryan

 

I was just about to ask a very similar question.
(My car 03 S 17% pulley and single mass flywheel a few hundred miles ago.)
Whirring/whining noise on my car. Just came about.
I had a tick noise a few weeks back, which seems to stop on it's own after a few days. I still decided to change the chain tensioner and guide rails.
Then a couple weeks ago I left my lights on at work, killing my battery. Jumped it got home, but the battery was toast. Got a new battery, and since then have had the whining noise. (Coincidence?)
Just like you rev based. Don't hear much at idle, but if I hold rpms at 2-500 clearly loud and easy to hear. Gets a little louder with more rpm's, but so does the car. Like you I changed the idler pulley no change.
Was thinking about the belt tensioner change.
The noise on mine does change when pushing clutch in when driving. I'm gonna try pushing the clutch pedal in with it in neutral, holding revs.
To see if I can hear the change more clearly.
I've tried the long screw driver, but need a scope to search better.

 

So I think I may have an idea as to what is causing the noise.....

i noticed that my coolant expansion tank has been leaking quite a bit (white residue all over and loss of coolant) and it kind of sounds like the hissing is coming from that area under the hood.

i tried the hose and stethoscope technique and could hear exactly where it was coming from other than just that general area.

Will replace the tank, since it needs to be done anyway, and see if that fixes it.

 

Harbor Freight and several other sources sell a coolant pressure test set which may be able to get a bit more pressure into your cooling system to diagnose a leak.

 

this isn’t my car, but this is what mine sounds like.

 

Couldn’t really make out much on the video. What I heard sounds like air.

 

I have the same noise, a 'whirring' sound from the right side of the dash. In my case in NZ this is the driver's side. My current theory is that it is coming from a very brittle and cracked boot on the intercooler. I have news ones on order.

It's one of the things that would 'whir' or "hiss" depending on engine RPM, and would certainly be audible from the cabin. I'll have the new boots installed as part of a much larger re-fit in a couple of weeks and will report back.

I would be curious if the others that have a similar noise also have intercooler boots that are cracking or perished.

 

Yeah, I realized that my initial description of the sound was probably not accurate. It does sound more like a hissing or "shhhhhh".

 

I noticed a common element, is the addition of a pulley, just out of curiosity did you also change the air intake? Say from either the stock or JCW design to a modified and /or open top airbox? This would change the sound you hear as the intake is sucking in air directly in front of the driver, and yes you can hear it. But this sound would change with the engine RPM.

You say the sound is from the Left Front, and there is the airbox, and down low is the steering pump, and the rad fans and centered is the water pump. With all the real moving spinning whirling things on the right (SC pulleys, Alternator, AC Compressor and so on).

The HVAC fan is located lower center, in the cabin of the car, with the air inlet on the Right Side, and if you hear the noise with the fan turned off you can rule that out.

So ... most likely causes ... Intercooler gaskets seals and or possibly that one vacuum hose that hooks to the manifold that runs under the intercooler (if this is disconnected the Service Engine Soon Light normally pops on after about 1/4 tank of fuel, this has been one of my personal nemesis).

And if you think the brakes feel a bit squishy, the vacuum line going to the Brake Servo may be in question.

Best of luck.

Motor On!

 

Thank you for the response.

Still on the stock air-box. I am actually going to take it to the dealer on Friday for an oil change and see if they can listen to it and help me figure it out.

so hopefully they will be able to pin point it and hopefully it isn’t an expensive fix.

 

On mine, I removed the belt tensioner last night. The pulley didn't seem to make any noise. Maybe a slight amount, perhaps it could be amplified with some rpm's.
The the dampener on it was gone though, pushed in it would stay in. The rubber bushings looked ok though, one had a slight crack.
So I ordered a new belt tensioner, even though I doubt it's my problem.
On a side note why don't they sell the tensioner pulley by itself? I doubt the spring wears out much.
Be better if just the pulley could be changed out.

 

Ok, so this MAY be an update.... I was able to put a mechanic’s stethoscope on a few different things under the hood and this is what I found:
- the supercharger (just behind the pulley) makes a very smooth whhhhiiirrrrrrr
- the alternator makes a growling noise
- I couldn’t get the stethoscope on anything else with the limited space.

So, are these sounds normal?

 

I'm betting both are normal.....I have put a stethoscope on many alternators and most have a type of "growling" noise.....the supercharger has gears inside the housing as well....there should be oil inside there as well

I would take the serp belt off and spin the alternator by hand to see if the noise is still there....it won't be as loud.....and I don't think that what you found is your "noise" that you originally posted about

Bryan

 

Hmmmm. Well, I don’t have the belt tensioner tool, so I am just going to take it into the dealership on Friday and just pay them to diagnose it.

 

Changed out the belt tensioner, no change for me.
The noise doesn't really seem to be there at idle.
It becomes loud pretty much when it gets to 2k rpm's. Then seems to get quieter around 3k, but not sure if it's engine and exhaust drowning it out.
Driving the noise seems loudest in 1st and 2nd gear.
When shifting the noise changes when pushing in the clutch pedal.
But in nuetral revving it to 2k to get the noise, pushing in the clutch pedal doesn't change the noise. It's only when moving, when in gear.
So now not sure if it's the trans? Don't think it's a tob since it would be doing it in nuetral I believe.

 

What did the dealership say was the problem?