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A newstrange noise...any thoughts?

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Recorded in the car, stationary, engine on tickover. I cannot work out where it is coming from. Sounds like an old kettle whistle. It isn't from radio, or power steering  or air con and I  am pretty certain not the engine compartment.  No noise when I rolled it down the road with the engine off. Maybe behind or under centre consol.  Wondering if anything to do with exhaust. Heard it briefly when engine was off and ignition (all lights) on, so maybe electrical.

 

As ever, any bright ideas welcome

 

 

You might need to turn up your volume....!

 

cheers.

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Could be the e-box fan. Its air intake is behind the glovebox and it makes a sound like that when its motor bearings are drying out.

 

It runs for a few seconds at start up, goes off and then comes on later when the DME needs cooling.

 

There is also a tiny fan in the HVAC unit control that can tweet away like that.

 

Other than those the main blower motor in the HVAC system can make similar noises but that is easy to rule out by switching it off.

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3 hours ago, THe39M5 said:

Could be the e-box fan. Its air intake is behind the glovebox and it makes a sound like that when its motor bearings are drying out.

 

It runs for a few seconds at start up, goes off and then comes on later when the DME needs cooling.

 

There is also a tiny fan in the HVAC unit control that can tweet away like that.

 

Other than those the main blower motor in the HVAC system can make similar noises but that is easy to rule out by switching it off.

 

Hi, thanks for all that.  I wasn't aware the car had all those fans!  I am fairly sure it isn't anything to do with the air con as the noise continued when I switched it all off.  I will see if I can find the e-box fan.  Maybe some WD40 will do the trick? 

 

I appreciate you taking the trouble to reply.

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I’m not sure if the e-box fan runs on after the engine stops but it might for a few seconds as the DME stays active for a shutdown self-test cycle after you switch off.

 

The small air sampling fan in the air con panel definitely runs on for a while when you turn it off. The one in my ex 528i twittered away to itself for some time even with the keys out.

 

The sintered bearings in the e-box fan motor can be improved with some oil but it is a bit of a job to get to it. Part of the joy of nine plus years of owning one of these cars is you get to do these jobs, twice!

 

You can manually activate the e-box fan using DIS if you have it.

 

One other thought is it could perhaps be one of the air flap motors in the aircon system. You can trigger those easily with the air direction buttons and recirculate function.

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8 minutes ago, THe39M5 said:

I’m not sure if the e-box fan runs on after the engine stops but it might for a few seconds as the DME stays active for a shutdown self-test cycle after you switch off.

 

The small air sampling fan in the air con panel definitely runs on for a while when you turn it off. The one in my ex 528i twittered away to itself for some time even with the keys out.

 

The sintered bearings in the e-box fan motor can be improved with some oil but it is a bit of a job to get to it. Part of the joy of nine plus years of owning one of these cars is you get to do these jobs, twice!

 

You can manually activate the e-box fan using DIS if you have it.

 

One other thought is it could perhaps be one of the air flap motors in the aircon system. You can trigger those easily with the air direction buttons and recirculate function.

 

thanks again. You are beginning to lose me with the tech talk!!  DIS?

 

 

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