98 f150 4x4 supercab shortbed 4.6 ltr

can or does water ever get trapped in that grille under the windshield/hood vent thing. i hear water and dont know where its coming from.

or can it be my heater core is clogged how do i know its clogged the heater works fine but when i accelerate i hear water trickling
how can a heater core get clogged? i checked the ac drain tube under neith the truck stuck a 31" flex wire up it and not clogged
no water leaking in the cab at all. on hear it when i accelerate.

 

This may sound stupid, but if you only hear it upon acceleration, it may be water in the bed. Is it definitely inside the cab? Has it rained or snow a lot there recently?

SL

 

its coming from the dash for sure and i have a hard leak proof tonue cover on by glasstite (breeze)