Evaporator Drain Tube: Service and Repair

Plenum Chamber Water Drain

• The draining of water from plenum chamber - A - may be impaired by deposits (leaves, various tree needles, etc.) accumulating in plenum chamber water drains - B -. The water level in plenum chamber - A - then rises if the vehicle is taken to an automatic car wash or in the event of heavy rain. Water enters via the intake shaft into A/C unit - D - and is blown by the fresh air blower (V2) onto the evaporator together with the conveyed air.






• If valves - C - of the grommets of water drains - B - (right and left in plenum chamber) are blocked by leaves and pine needles, it may cause the drains to freeze up in winter and water can no longer drain out. After a short drive, heat emitted from engine and exhaust system melts the ice in the drains again and water may drain off again before vehicle arrives at the workshop.

• Water drain grommets - B - are snapped into the plenum chamber openings from above.

• Depending on the vehicle equipment and vehicle version, grommets - B - may not be accessible from above or only with the plenum chamber bulkhead. In vehicles in which grommets - B - are not accessible from above or only with the plenum chamber bulkhead removed, these can also be cleaned, removed, and installed from below with the wheel housing liners removed (removing and installing front left wheel housing liner - A - and/or the front right wheel housing liner ).






Preparation

- Switch off the ignition.

- Remove plenum chamber cover - A - and the plenum chamber bulkhead ).






• To prevent water from running via intake shaft - C - into the A/C unit when plenum chamber cover - A - is installed, plenum chamber cover - A - must not be damaged. Plenum chamber cover - A - must be correctly and completely engaged in frame - D - of windshield - B -.

Checking and Cleaning

• Use a commercially available and illuminated endoscope for example, to check the water drains that are difficult to reach. It is best to use one that has a flexible waterproof head.

• Use a commercially available flexible gripping tool to clean, for example, coarse dirt from difficult to reach water drains. Then wash out the any remaining contaminates.

- Clean left and right water drains - B - (two on the right and two on the left).






- Clean debris (leaves, pine tree needles) and other contamination out of plenum channel - A -.

- Check grommets - B - for proper functioning (valves - C - must not stick or be obstructed by dirt)

Removing

- Remove grommets - B - by pressing them from the top (or from the bottom if necessary) from the water drain openings in the floor panel of plenum chamber - A -.

Installing

- Install grommets - B - by pressing them from the top (or from the bottom if necessary) into the water drain openings in the floor panel of plenum chamber - A -.

- Check grommets - B - for proper functioning after installation. Valves - C - must not stick and must close.