mikesd1980

I know I am not crazy or nothing but when I stop red lights and stop signs I hear water washing around like in a bottle on the passenger side of the care. It happens when I hit the gas from the stop also. Any info on what it can be?

derfA8L

Could be clogged A/C condensation drain tubes or clogged up windshield cowl drain causing water to build-up. The former will cause a nasty odor when the A/C is run, and could leak into the passenger cabin. The latter will most definitely flood into the cabin. I'd have it checked out ASAP before your feet get wet ;^) Both are known issues with the A8, and Audis in general.

The drain tubes are engineered with a sort of valve at the ends that are supposed to prevent debris from backing up into the tubes---problem is, they can also cause a blockage thus preventing the tubes to drain. I've been told that some dealers simple cut the ends of the tubes and do away with the back-up valves to prevent a re-occurrence of the problem. If the car has been left outside and debris like pine needles or deteriorated small leaves have been allowed to collect in/under the windshield cowl, this can create a blockage and cause water to collect and overflow into the cabin.

MP4.2+6.0

First check the dumb stuff of course like a water bottle that has lodged under the passenger seat. If so, gotta own up to it too...

More seriously, check passenger carpet immediately to see if wet. If so, without delay you need to stop using car, wet vac it, pull up carpet on the side and get water out underneath, then dry the car for some days. The normal reason this happens (besides open windows and sunroof) is a problem with the undercowl cover--the big one below the windshield where the extra filter is in the rear of the engine compartment. Look especially at that HVAC filter cover, since from there into the heater area and then down to the floor is a direct passage given the intended air flow. Also, be looking for standing water, likely decause of blocked drains in that undercowl area. If so, report back in for more instructions. A notorious issue with C5's which had a terrible design.

Separately, need to see if HVAC drain line is blocked. If so, the AC condensation is ending up on your carpet. Then usually not as soaked, but still needs to be dried to avoid issues and mold. One check there is after parking an a warm day, look under car around front footwell area behind front tires some minutes after stopping (call it 10-20). If you see clear water on the ground, the drain is functioning, at least at some level. No water on a hot day (unless you live in a very, very low humidity area) would be a definite warning sign.

Not sure what is under the passenger floor on an A8. On the A6 it was a main wiring harness and the not inexpensive tranny computer box that didn't like water baths.

Problems w/ replaced windshields or sunroof drains could also be suspect, but those aren't very common

mikesd1980

Thanks for the response. Okay I check the floor front and back of passenger and driver's side. There is no water anywhere. Since it been so hot in NJ the last few days. After parking I do notice the water from the AC on the ground. Is there anything else that I am missing. I read stories about the back up cowl and AC drains. Dont want to ruin my car yet. I have to drive about 12 hours next month and want things to be perfect with the car.

MP4.2+6.0

from the practical checks you did. You could take off the cowl cover, look for any water in there, and in any case vacuum or blow out any debris you find.

The swishing noise must be something else.

Mister Bally

Get a 2nd person in the car with you. One drives and one finds. My son has helped me find squeaks, rattles and buzzing several times now.

mikesd1980

Thanks for the advice. I will get someone else to drive and I will try and find the issue this weekend. If I find anything I will post. Thanks again.

MP4.2+6.0

it is the car being quiet and then the fuel sloshing around in the tank, especially toward empty???

W12s solve this by just pushing harder on the gas or brakes to just plaster the fuel to front or back of tank wall. Presto, no sloshing Seriously, I've heard this sloshing in my old Chrysler T&C van and likewise my Toyota Sienna (Japanese is no better here) once in a while, but not in any of my recent Audi's.

mikesd1980

I actually thought of that. I believe I have a half a tank of gas at the time. I have to fill up after work so i will check again. For the past 2 weeks my brother thinks he smell anit-freeze. Would the clogged cowl drains give that kind of smell? I am getting alittle nervious. I still dont have water inside the car though.

Tertius Buys

Hi did you solve the problem? I have a similar noise almost from the chassis at the doors, very hard to pinpoint it exactly...Looked at the chassis but found no drain holes there. Also when I stop or accelerate.