Help...Water leak

[Ivan]

The blend doors are what the red/blue HVAC slider control. They either close allowing no outside air in, or open to allow outside air in....they are what the cowl's main purpose is - if you have them opened, they need to get outside air from some place that won't have any smelly fumes or anything....that's why the vents aren't in the engine compartment, bur rather below the windshield.

Most newer cars will have the hood sort of overlapping these vents so water can't be rushed in when driving...which the Cherokee doesn't have, so water can come into them whenever. Take the cowl off and check the drain. If it is backing up, the water will pass right through the blend doors.

There's a covering under the cowl that keeps water from pouring straight into the air intake. Remove the wipers, remove the cowl and you will see how it's covered.

Any water that does manage to get in the area under the cowl is diverted to the sides. Unless these drain areas are packed with leaves an other debris, they are usually pretty hard to plug up due to the size of the opening. There is an air intake plenum that pokes up through this area under the cowl cover, and is supposively sealed off with foam. You have to cut an access hole just above the air intake, to be able to reach in and seal the foam area off with silicone. I thought that's where I had a leak, but it turned to be in the blower area through the firewall instead...

Besides, if it's leaking in the air intake area, it would most likely drip into the passenger side, but anything is possible. Try sealing the air intake foam seal with silicone and see what happens. At least you will eliminate an potential leak in the future as the foam seal breaks down over time...