What is supposed to clip onto this? Is there any sort of metal mesh vermin shield made for this?

 

If there is something, I need one also! I don't think our years ('99/00") had anything there.

 

I believe it's just open. I sealed mine up completely when I did my cowl intake. I can't recall exactly as it was many moons ago, lol...

 

What you see is stock, nothing is missing. I made a box of hardware cloth(1/2 " mesh screen) that fits over it to keep the mice out of the air box.

 

Like exasemech said.
That is what it is.
There was something years back that I am pretty sure I read about putting an older air box in a newer Jeep.
Something about that opening being larger I think.
I poked around about it for a second but it didn't really seem that important or beneficial so......

 

On early jeeps a preheat air valve was in that location. some early housing suffer from deformation do to no stiffener ribs moulded into the sides of airbox. deformation can allow filter to fall out of position and be bypassed, a design flaw the early box is flimsy. the preheat is however needed to pass my california smog test, I run the late box in my early jeep, except on smog test days. I need to get around to grafting the preheat valve to a late box.

 

Yet another item a 3D printer could revive from the dead. I’m curious what this preheated consisted of. Was it for the 2.5VM diesel? My old ‘06 Ram Cummins had a factory electric airbox preheater as that engine setup did not have glow plugs.

 

My '88 has one. It's a vacuum operated preheat valve. When cold out, the vacuum close a "flapper" so the airbox draws air through a hose connected to the exhaust manifold. Once the air warms up, the valve opens to allow fresh air from the front of the air box. On mine you can see the front extends into the cavity.





A bimetalic switch in the upper airbox cover controls the vacuum to the diverter.





As others have said, It's considered part of the emissions systems here in CA, ditching it is a no-no. In fact I failed one year due to the tube connecting it to the exhaust manifold was missing.

 

My '96 had a corresponding hole in the front panel, so a true, OEM, cold air intake, or would've been if there'd been a bridging piece/extesion. On later models you can still se the dimple where the hole would've been.

My '98 has a snorkel which connects to that "nose" with a right angled adaptor for the hose.

 

On my 92, the airbox connected to the front air intake hole but no valve. The 01 has the short pipe, probably to suck up engine compartment gasses