Humming noise from the back of the car?

Was just wondering if anyone knows what a humming noise from the back of the car could be? I only hear it after shutting down, and it can only be heard for 10 seconds or so, which means I never get a good
chance to locate it exactly, but I can hear it's from the rear. Sound like a pump (?) summing for a short while, but not always...
Car = BMW 528 Touring 2000.
Cheers
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US based car? Carbon Fuelvapour filter or feul pump.
Euro based car, Fuel pump.
Erik
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snipped-for-privacy@gmail.com wrote:

If you have the self-leveling suspension (all US tourings came with it) - there is an air pump inside the spare tire well (under the spare) that may run for a few moments after shutdown.
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On Wed, 12 Dec 2007 13:29:35 -0800 (PST), snipped-for-privacy@gmail.com wrote:

Look for a drunk passenger or the mother-in-law under the seats.
--

Sir Hugh of Bognor

The difference between men and boys is the price of their toys.
  Click to see the full signature.
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Only if it's humming "Moon Along the Wabash." Does this car have pneumatic suspension by any chance? --scott
--
"C'est un Nagra. C'est suisse, et tres, tres precis."

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Could just be the antenna. Are you new to this car??

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Jack wrote:

The painted on antenna on the rear window? It hums? Amazing.
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Have you checked to see if Bill Clinton and Monica have hitched a ride?
My guess is that there are ventilation system flaps that are operated by a motor or by vacuum, and you are hearing these flaps close. I would not give this issue another thought ... (and I'll try not to think of Monica either <crap, now that image is burned into my brain>.)

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