Passat Plenum Chamber Drain Holes

[knoxman]

I realise that there are masses of posts on this site regarding water ingress in the Passat, and I have had my own bitter experience of this in my own car - a 2005 Passat Highline Estate with 130 bhp TDI engine.

After the recent heavy rain, I decided to check the plenum chamber on my car. After removing the plenum plastic cover, I found the area below the battery clear of water, but the space below the brake servo (on the driver's side of the chamber) had some water trapped in it. I sucked this water out with a length of plastic tubing connected to an old washing up liquid. I then tried to find the drain hole which might be blocked and causing the water to collect, but was unable to see the hole.

Can any member please tell me precisely where I ought to find this drain hole so that I can clear it. Many thanks.

[Crasher]

One hole I under the servo, you can’t see it but you can feel it with the battery out. The other is under the battery tray. DO NOT poke the drain bungs out, they are one way valves and are there to stop nasty fumes being drawn into the heater from under the car.

[dickturpin]

I bow to Crashers superior knowledge on all things VW but I took my bungs out and have no smell in the cabin.
I poked out the bung under the brake servo from beneath with a lonnnnng screwdriver.

No water problems either!!

[knoxman]

Many thanks for above responses to my query. Is it possible to access/clear the blocked bung/drain hole under the brake servo without removing the battery, perhaps using a stiff piece of wire shaped to fit around the body of the brake servo unit? (I am rather pressed for time....)

[Crasher]

You can do the one under the battery from below but the one under the servo needs the battery out.

[yaman]

(I am rather pressed for time....)

We all are, and that's exactly why they should be removed

Regards
Jim

[Crasher]

I say poke them clean, don’t remove them.

[Peter D]

They are specifically designed duck bill water vents and should not be removed. They should be cleaned flushed and sterilised, dettol or the like. A hot engine gives off fumes and the bungs is designed to stop that air from entering the plenum chamber and your head. In traffic queued up the exhaust fumes are blown under your car and rise up to the plenum chamber. With the bungs operational you are only breather the air from just in front of the windscreen. Regards Peter

[yaman]

With the bungs operational you are only breather the air from just in front of the windscreen. Regards Peter

Throw them away


The bungs would have to be blocked to be fume-proof, and we all know what that means... 1 shower of
rain or 1 car wash and you run the risk of serious damage. Its a flawed theory, and design!

The mass of air-pressure that sits on the plastic grills, on top of the plenum chamber, far exceeds any
pressure trying to rise into the bung-holes from underneath, and this increases with speed because
of air-flow. They ******-up with these things, big-time.

Regards
Jim

[Crasher]

They are specifically designed duck bill water vents and should not be removed

Thank God, at last someone agrees with me!