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Discussion Starter #1
I have a friend with an 03 330i with about 60,000 miles. He called me with a request for assistance diagnosing a squeal. He described it as coming from the driver's side air vent or instrument cluster. Based on the results of my search in this forum, we ran through the following steps to diagnose it:

1. Turned the AC off, first just the compressor and then the fan too...no change in noise. This let me to rule out the blower motor or the resistor pack.
2. Turned the stereo off just in case...he had some stereo work done. No change...
3. The sound occurred with water temp at normal. It is not a couple of seconds at cold start.
4. There was no change in the sound with increased RPM's. This led me to believe it was neither a belt nor a tensioner, nor the power steering pump.
5. The sound occurred both moving and stationary
6. The squeal stopped when the engine was shut off, but key still in the on position
7. The noise is not constant...it comes and goes.
8. I had him rev the car to redline and there was no change in sound, leading me to believe it is not the VANOS unit.

He claims it sounds like a fan going bad. I do not recall any fans in the instrument cluster. Besides, it would not stop with the engine off. I also don't think the tachometer has a cable, but is electronic. Is that right?

Any help would be appreciated. Thanks!
 

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Hmmm - maybe a small vacuum leak or crack in the intake boot? A change in pitch may not be noticeable at varied RPMs if the frequency is high enough.

I take it the car functions normally with no check engine lights?

Ken
 

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Take off the belt and see if the noise goes away this will completly rule out anything driven by the belt(just don't drive the car very far or long with the belt off!!!)
 

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Discussion Starter #4
Thank you for the quick response. The car just returned from Inspection II with no findings. No CEL and no improper running. Gas mileage seems normal.
 

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It still could be something driven by the belts it is a real; quick and simple thing to do, otherwise go buy a stethascope and listen to the bearings to try to determain if one is making to much noise
 

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It still could be something driven by the belts it is a real; quick and simple thing to do, otherwise go buy a stethascope and listen to the bearings to try to determain if one is making to much noise
Should this self diagnosis be done with an automatic also? It is more of a PITA because of the fan but I'm just curious if there is anything that can go wrong with starting the engine and letting it run for a few seconds with no belt on an automatic.
 
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