Cooling system question
 

Ok i drive a 90 pioneer and just trying to figure out what exactly this pipe is called other than a 3 way?
https://cimg8.ibsrv.net/gimg/www.che...4775932923.jpg

Jeep refers to it as a "tee". Part #8 here:

https://www.moparpartsgiant.com/part...~52003878.html

You can make one from some copper tubing if needed.

Tee
 

discontinued of course

How old is your radiator? Might be a good time to consider updating to an open cooling system with summer coming.

Just over a year

Depending on cost.. you still might want to at least run the numbers on what Cruiser said.... the guy knows what he's talking about... especially with that era XJ.
It still might be worth your while to convert to an open system.