Pop the hood and try to find the source of the noise before it quits. You might also consider having a mechanic listen to it. If you have anti-lock brakes, you might be hearing the pump replenish any pressurized brake fluid that may have leaked down. There might also be a pump for an automatic load-leveling system that's running.
On many vehicles the load-leveling pump won't run if a door is open so you might try leaving your door open to see if the noise is still heard. On some anti-lock brake systems the power brake assist comes from the pressurized brake fluid. Pumping the brake pedal a dozen times will deplete the pressure and the pump will turn on again and run for about ten seconds to build the pressure back up.
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Wednesday, August 10th, 2011 AT 8:38 AM