I'm not going to need the small bypass inlet on the thermostat housing. The little one on the left in the photo.



What's the PROPER way to plug it? Can I pull the brass fitting out and tap the hole for an NPT bolt? How would I get that fitting out? Is it just pressed in there?

 

I would. Add a piece of hose over it and then plug the hose with a bolt then zip tie it in place.

 

They sell water hose endings just for this purpose at every auto store for under 5 bucks. Pep boys, autozone, advanced, etc etc, just rubber endings and then add a clamp to it you're set.

 

I think you could buy a obd 2 housing.
THis goes to the upper rad hose housing right.
What is it for on obd 1 cars, since obd 2 cars dont even use it.
I read that its a breather heater for the valve cover to intake tube. THat why the valve cover breater hose and that coolant hose are connected by those metal tube that are together.