Water Dripping
Was it because this particular car wash machine sprayed too much water so it went through the HVAC system?
Is it something getting aged?
Anybody had the same experience? Thank you!




1. check to see if the cowl below the windshield has leaves blocking the drain slots
2. I think there is something on the manual (or read somewhere on this thread) that whenever you are using a automated car wash to make sure to turn the air flow to recirculating mode so that the intake will close and will prevent water from coming in.
Get that dried asap as you do not want any rusting or worst molds growing inside your car.
You just remind me that I used to turn off the HVAC when using automated car wash but not this time. That might solve the problem.
But just kind of curious that will pouring rain have the same effect? or it's because high pressure from car wash?
But when I touched the panel under glove box where the cabin filter located, I could feel it's wet.
The water must get inside through the HVAC air intake.




TPete19 is also correct as you may also have a clogged or disconnected moon-roof drain and the only way to find out is to get a garden hose and hose down the entire moon roof section by section and see if you will have water dripping inside there but from how you described it my bet is water came inside the hvac opening.
If it indeed came inside the hvac opening I would suggest to take out your cabin air filter and check if it is wet. If it is wet then water did came from the hvac opening and you
MUST replace that filter (or make sure it is 100% dry) or else mold might grow there. Also run your fan to high for 20-30 minutes to dry out the ducts.
I once have a Cadillac Catera which have a very poor hvac intake design that if there is a small debris on top of the opening you will have a flood inside your car. One time I have a ice skating rink inside the front passenger floor as we had a nasty winter rain in the evening then came midnight temperature went to -2 and froze the water inside. Took me the entire day to let it thaw and vacuum out the water little by little.
Last edited by shotgun_banjo; Nov 7, 2015 at 02:10 AM.
Trending Topics
Luckily I haven't replaced the cabin air filter yet. It's time to replace now.
TPete19, I think the clogged moonroof isn't likely. I live in rainy city, all day rain. I don't see the same symptom. Thanks.
I'll try the car wash again with HVAC off next week. The new 24hr car wash is offering free car wash for November.
The Best of Mercedes & AMG




Luckily I haven't replaced the cabin air filter yet. It's time to replace now.
TPete19, I think the clogged moonroof isn't likely. I live in rainy city, all day rain. I don't see the same symptom. Thanks.
I'll try the car wash again with HVAC off next week. The new 24hr car wash is offering free car wash for November.
Just an update, after 30mins long wait for car wash with HVAC off yesterday, I didn't notice any water dripping. I didn't switch to circulation. Perhaps the water can get in but not that much to cause dripping. This car wash tunnel is twice longer than the one I used to go.


