Cleaning underneath the cowl (below windshield) ???

[83Ram50TDinPA]

How do you do this ? Seems cowl is not removable. Take fenders off ? I have a feeling 40-years of crap has built up down there.

[Not a real meme]

I believe most just use a vacuum to clean it as blowing it may just clog it up a bit more.

[83Ram50TDinPA]

Impossible... cowl will not come off... cannot vacuum through the cowl grill.

[geezer101]

There are block off plates under the dash behind the glove box and the instrument panel on either end of the firewall. You can also go through the inspection cover from the inside of the engine bay into the air channel. I think you can also undo the bottom fender bolts and lift the bottom ends of the fenders away enough to flush them out with a garden hose (you may want to put a towel in the foot wells just in case any water backlogs into the cab) This is a time bomb hidden in these trucks and if they aren't cleaned out every few years they are left susceptible to rot, plus if they block up they can cause water to pool in the foot wells in the cab when you get any decent amount of rain.