My car (95 E420) is doing the same thing and I'm wondering if it's normal or not. I spoke with a couple of mechanics at my local dealership and they said that this is part of its normal 'test' cycle following the start of the car. Does this so called 'test' actually run the pump?

__________________
1995 E420
1998 SL500 Sport
2009 E350 Sport
1995 S500 Coupe
1992 500 SEL