2021 Frontier SV CC 4x4; 2018 Frontier SV KC 4x2
It’s an air box. Dust & debris are gonna come in with the air. They will accumulate in the box under/before the filter. That’s kinda the whole point.It seals fine enough to function, sure but it could use improvement. I have an Xterra and Frontier and they both accumulate a lot more dust and debris in the box than any other car I’ve dealt with.