Hi, my 2001 3500 DRV has substantial damping of front carpet when it rains. The problem starts at the plastic grill at base of wind shield at rear of hood. When I open the hood and slowly run some water directly into that grill I not only see some water dripping under the dashboard inside the van but also water dripping from various mounting holes drilled into the metal underneath that grill in the engine compartment. The latter are just in front of the firewall causing water to drip on everything below including the PCM.

I intend to seal off the grill itself which should be easy enough to do with the right tape. I suspect the purpose of the grill is to keep rain water from running up the hood onto the wind shield at higher speeds but with such a sharp forward drop off on the hood I don't think I really have to worry about that. My question is does that grill serve another purpose like venting air to the part of the engine behind the firewall under the "turtle" or anything else?
Thanks

I popped the grill out and there is only a well to collect water which empties at each side onto the ground down the frame. On the top side of that well just under the grill are about 5 flat metal supports the 2 largest of which are about half a foot wide and hold the base of each windshield wiper. My well is water tight but rain coming into the hole for driver's side wiper and the 2 slots in the grill next to it run on top of that flat metal support and forward dripping into the engine compartment some of which finds a way onto my floor. That water never drops into the well but goes under the grill forward and out. It can be a lot of water when you brake and rain water on your roof runs down the windshield into the grill. I can't see that there was ever any seal to prevent that leak path and suspect others may have it. I have some aftermarket cables coming through my firewall which is probably how it gets to the inside floor. A simple ridge of sealant on the forward lower end of the flat metal support now channels that water into the well with no more leak.