Does anyone know what this black plug part is/does. My 2000 xj is leaking coolant like crazy from here.

 

That's the "I'm buying a new radiator dealeo".

 

??? HuH? Not really sure what I'm looking at there. 87-90 Jeeps have threads about there for a large diameter temp sensor/switch for the Efan. Suppose if somehow that plug leaking were the only problem, a guy might pick up that switch from on old jeep and use it to plug the hole. Heck, if you leave the wires in it you could hook it to a relay and have it control your Fan. (2000 does it different)

 

It's.... a plug.

It's not plugging.

Replace it.

Problem solved.

 

Do you know if it's NPT, or comes home on a gasket? It being leaking suggests someone got that one wrong. ( I think it comes home, not NPT) It's likely that the fan temp switch that (that may well be for), (made of brass), would plug it as well as anything else. And give the option for a Renix stile Efan. (Renix may or may not need a computer working to tell when 210* is exceeded....

It's looken somewhat custom and has the bung..Renix it I say!

 

I'm guessing someone took an old model radiator and installed it in yours. So either replace the radiator or pull the plug out and see if you can find a new gasket/o-ring for it. maybe add a little thread sealer to the threads for extra security. my first guess was a plug for the auto trans cooler lines but that wouldn't be leaking coolant if it was.

 

Yeah I'm thinking the same thing judging by the welding job. Great thanks, I'll play around with it but might just be time for a new one.

 

it also appears to be an aluminum radiator and I wouldn't be surprised if a manufacturer just designed their Rad to fit the most model years possible since there were very limited changes from one year to the next. most notably being the Temp sender for the fan being in the Rad.