What is this ?

There is an air inlet behind the grill on the drivers side with a round flange (didn't measure but about 5" across) inside the engine compartment, is there supposed to be anything hooked up to it going to the air cleaner (air cleaner inlet points to passenger side) or is it just for cooling ?

 

It's the heater intake.

 

Ok, thanks, I found a picture of it online now, I don't have a box surrounding the heater core. I'm sure I can build one or find one if I decide I need it, but I don't have or plan to have a top on so the heater won't matter anyway.

 

Maybe defrosting the windshield. Maybe not.

 

Not

 

It'll keep your right foot warm!

 

Wouldn't know. Mine did not come with a place to even put a heater.

 

With no top, there's no frosting on the windshield. Same temperature, inside and out. Moot.

You can make it frost by parking it in a cold (insulated) garage and bringing it out into the warm. But it will frost on both sides!

 

The pics I've seen have not had the square diverter box, just the round hole with a mounting bracket on the engine compartment side for the air hose to clamp to. Was this an add on later?

 

Not sure, the way it's mounted and the attaching hardware looks factory, and it was originally the same colour as the body.

 

I have 69 & 70 CJ's that look just like that.
I'm unsure when it first appeared, but it is stock.

 

You talking about the scoop in the drivers side of the grill in front of the radiator on the early's?

 

Yes

 

My '57 does not have it but my '62, '66, and '71 all do. FWIW