Clogged drains can allow rainwater to accumulate in the plenum tray (at the base of the windshield). The water may leak into the vehicle's interior, brake booster, or electrical components, which can lead to major problems. Our technicians recommend keeping the tray clear of leaves, pine needles, and other debris.
Various Probelms Caused by Clogged Plenum Tray Drain on Audi A4 Quattro
Average mileage: 151,000 (77,000–260,000)
20 people reported this problem
Had water in car on floor in back--was after heavy rain. Never knew there was this tray. Mechanic said it was clogged with leaves (it was autumn) KEEP THIS Tray CLEAM!! took over $1000 to fix everything following water damage!
1999 Audi A4 Quattro 170,000 mi, Visitor
Water was draining into the car on the left hand-side and causing major flooding inside to the point where I felt I was the Captain of the Titanic. The cause was the drains in the plenum at the base of the windshield not draining fast enough and then overflowing into the pollen filter housing and traveling through the vents to the inside floor. The solution was to remove the small drain hose that passes through the rubber grommet in the center of the plenum. The little drain hose is still connected at the source near the pollen filter but the rubber grommet was chocking the hose, so by pulling the hose out of the rubber grommet and letting it drain into the pelnum it drains faster and has worked well for the past few months. I might try to further increase the drainage capabilities by removing the rubber grommet completely as suggested in other posts. Good luck to you all.
1996 Audi A4 Quattro 154,000 mi, Visitor
Dealt with this issue more times than I care to discuss!The water begins to impact electrical system so stay on top of this! The final solution was to get rid of the rubber drain plugs (one is under battery, other is near brake servo) to allow the water to drain better. Also, blow out the area w/ a compressor every couple of months.
1996 Audi A4 Quattro 145,000 mi, Visitor
rainwater accumulates in rear right passenger floor. wet vac water out, cannot find the problem.
1999 Audi A4 Quattro 260,000 mi, Visitor
I have not found a solution yet, please help! my windows now do not work, electrical issue and my car is flooded inside
water collecting near drivers left foot corner, plugged up drains, finally fixed 2nd time at dealer.