Foul Odor from Vents
It usually clears up after a few minutes, but still annoying.."
While other guys are discussing dashbaord design here, I have a NO COST suggestion for the FOUL ODOR problem. In the W211 there is a water-catch compartment on either side of the rear of the engine bay - rain water from the bonnet vent runs into these and exits via a small drain with a rubber spout into each wheel arch. Those drains are constrictive and can block with leaves and dust, causing stale water to accumulate at the bottom of these compartments. Even without blockage, there is an accumulation of mud and debris over time. That is often what smells, as it lies directly below the aircon intake filter. Solution that sorted me: Remove aircon filter housing, pour lots of hot water and a deodorising cleaner solution (I used Toilet Duck!!) into both compartments and let them rinse out well. If you dont see the water emerging from the arches behind the front wheels, the drains are blocked - must be cleared. Allow to dry with bonnet open. My 2003 E240's stale smell has been gone now for 4 months.



