Cowl: Testing and Inspection

Plenum Chamber Water Drain, Checking And Cleaning







NOTE:
- Drainage of water out of plenum chamber may be impaired by deposits such as leaves and pine needles accumulating in the water drains. If the vehicle is then driven through a car wash or in the event of heavy rainfall, the water level in the plenum chamber will rise, water will ingress into the air conditioner unit through the openings - A - (on right and left next to fresh air blower), which are actually intended for water drainage, and will be blown by the fresh air blower onto the evaporator together with the air conveyed.







- The two water drain sockets - A - and - B - in the plenum chamber can only be replaced after removing gearbox or air conditioner unit.
- Coarse dirt can be removed from the drains and the area beneath the air conditioner unit with a commercially available flexible gripper tool, for example, without removing air conditioner unit, gearbox, pump valve unit and brake servo. Fine deposits and sludge can be removed for example using a thin water hose or a pressure-feed spray gun V.A.G 1538 and a flexible nylon probe V.A.G 1538/2, or equivalent. In the event of particularly stubborn dirt, better access can be achieved for example by removing the pump valve unit.
- If the water drain sockets - A - and - B - are clogged with leaves and pine needles, the drains may freeze up in winter and prevent water drainage. After a short journey, the heat emitted by engine and exhaust system melts the ice in the drains again. By the time the vehicle arrives at the workshop, the water may have drained out of the plenum chamber again.