Water leak into Air Box and onto passenger Floor board
 

Hello,

The Vehicle in question is a 2005 Chevy Express 3500 with the 6.0L.

I hope everyone is well. I was wondering if I could get some guidance on this issue. I have currently removed the Wipers and plastic grills. I see no way for water to be entering this air box. I checked the Motor gasket looks good and resistor pack which also looks good. The amount of rain water that pours into the cab is telling me there is a bigger gap or issue somewhere. When it rains alot or go to the car wash I can turn on the A/C fan and hear water sloshing around, at this moment water starts to pour into cab on passenger side. Where does this model van pick up the Vent air? Is there a Drain hose I cannot see that maybe clogged? I have tried to find any information on this and only come up with Tahoe's, Silverados and older Express vans who have had similar issues. Thanks ahead of time for any support and knowledge. Very much appreciated. Thanks!

Yeah you need to getup under there and make sure the climate control housing water drain is working, not clogged up. A small spring works best so you can pull the debris out, not shove it back in with an air-pressure hose. It will be near the bottom of the firewall, at least on cars and pickups.

Thank you for the recommendation, will go check now!

For those of you with the newer Express vans the problem was under the right side vent louver. Once removed with Wiper arm you will see a cut out in the frame on the bottom near the middle of the windshield. I was looking for a rubber hose and this is an actual plastic molded tube that dumps behind the Passenger side down bear firewall 3/4 of the way down. It was clogged with dirt, leaves, etc. I had to use a water hose and metal hanger to unclog. At the bottom the drain is held closed with a rubber flap with what feels like a magnet keeping the outlet side closed. Hold open with left hand while cleaning inlet side until water flows properly. For me what worked best was to turn van to Battery power and turn on to set the damper doors to close off cab of the van. I had removed the motor as to clean out the heater box also which was full of debris also. Hope this helps those of you who may have the same issue I did. thanks!