The car had a nice long rest during the holidays. I got in yesterday to make a run and I hear a whistle (high pitched) inside the cabin. I stuck my head in the engine bay and no whistle to be heard. It is definitely inside the cabin. Its so damn high pitched that it is hard to DF the darn sound. It "appears" to be coming from the center dash area.

It is not affected in pitch by engine RPM.
It stopped after the car was fully warmed up.

I just started it 5 minutes ago and the whistle is back.
I let the car run for a few minutes and the sound is definitely coming from the dash, either center or just left of center.

The radio is off. I turned it on changed a few input modes, nothing, I turned the radio back off, no change.

The heat/AC was off. I turned on the heat for both sides, no change in noise level or pitch. Turned heat off, no change.

Vacuum gauge reads -17 at idle (normal) Gauge is AeroForce electric (reads from the DTC connector).

I shut the car off and it continued to whistle (same pitch and volume) for a short time (eliminates fuel pump) and slowly went up in pitch as it faded in volume. That leads me to think some kind of vacuum leak??? It took about 30 seconds to finally silence.

Any suggestions?

Elmer

 

Nice bit of sleuthing. I was gonna guess that it was the HVAC.

This is just a stab in the dark, but try pulling the fuse for the radio.

Maybe when the radio is switched off, the separate amplifier is in some kind of standby mode and is 'leaking' a little noise out to the center speaker.

The only reason I would even suggest this is that I've heard professional amplifiers do this.

Wild guess for sure, Good Luck.

 

Just made a few errands. The car was fully warmed up. I noticed the sound was affected by the motion of the car (bumps). After my second stop of my errand run, the whistle stopped and did not return for the last two stop/start situations. So, now the whistle is gone. I expect it to return tomorrow as it is going to go to 22 tonight and the car will be cold. I'll give a report on the radio fuse thing after I get the car cold and test it in the AM.

This is going to be a pisser to find and fix.

Elmer

 

Our 2009 nav makes a hum/whistle sound sometimes, but not very loud.

 

I am sooooo embarrassed. The damn whistle turned out to be in the engine compartment and it was the brake booster.

So, this is an E-Force bulletin now.

If you have the E-Force kit, your vacuum supply to the brake booster is now coming from the front of the SC unit. The hose is non-supported for the entire run AND pulls on the brake booster check valve and gasket. My E-Force has been on for over a year and the bouncing and vibration has taken it's toll and wore a hole in the rubber gasket. THAT was the leak. The replacement cost me $22.

I highly recommend that you use a wire tie and draw the brake booster hose to the rear support that holds up the "wing" cover of the supercharger. Tie it any where you like but don't let it hang free in the wind or you may start whistling Dixie too! By using that support, the hose has no tension on the gasket and won't bounce around wearing out the gasket.

May the E-Force be with you!


Elmer

 

Elmer, had my e force almost a year now too, no whistle yet, great post and thanks for the info, could you snap a pic to make it easier for us technically challenged folks? cheers.
Steve

 

No whistle here either but I always noticed the slightest movement of the brake booster vacum hose and it would start whisting as air escaped. This anytime I touch it while doing something under the hood.

 

Same here, a picture would be great so I know what I'm looking for. Glad you found the problem so quickly.

 

Ok, here's what I did to fix and stop the whistle from coming back.

This is a full view of the vacuum hose coming from the front of the SC back to the brake Booster





This is a close up of the wire tie holding the vacuum hose tied back against the rear support post for the "wing". The brake booster check valve is perpendicular to the brake booster and the hose is firmly held in place to stop the movement caused when you hit bumps in the road.




Elmer

 

Thanks for the photo Elmer, I will check mine out.