Another common water damage problem is found in the cowl panel (cavity between the engine firewall and the cabin firewall at the base of the widshield) of most Mercedes cars. This is where the climate control system draws in fresh air from the outside. Older vehicles can have corrosion or rust here. This area is almost imposible to repair once it has rusted through. It can be patched but it will leak again within a few years. The replacement panels are available from mercedes but are very difficult to weld in place and usualy require removal of the dashboard, engine and other components to install properly. The cowl cavity also has problems from clogged drains.

An incrdible amount of water can run off the roof and windshield and collect in this cavity. Debris from leaves that collect on the windshield will restrict the drain to the point that the cavity fils with water and floods components in the cavity and overflows through the fresh air opening of the climate control system into the cabin of the vehicle.

The Mercedes SLK 170 chassis is especially suseptible to this condition. Even minor overflow from restricted drain will cause water to flow across the blower motor, speed regulator, radio amplifier and wire harness connectors. The water is sometimes not discovered for several days and components start to fail; blower motor speeds are erattic or stop alltogether, radio stops playing, warning lights appear on the dash, and the vehicle begins to smell musty inside. The carpet and floor insulation system on late model mercedes is made of sponge like foam that is molded to fill all of the irregular cavities under the carpet. The foam is over 6 inches thick in some areas. This foam soaks up and hold water like a sponge.

All interior components must be removed to access problem areas.

This SLK was flooded by the customers own lawn sprinkler system. One of the sprinkler heads came loose and the stream of water shot way up in the air and back down on the windshield. The water drains in the cowl at the base of the windshield were slightly clogged with debris and they could not handle the huge volume of water. The water overflowed through the fresh air opening of the AC system and flooded the inside of the vehicle. We had to completly dissasemble the interior of the vehicle and replace many of the electronic components; Blower motor and regulator, radio amplifier, Tel-Aid control module / comunication module, Radio and the ABS / ETS module (mounted under the hood on the antilock brake pump. must also have been electical short circuit related).