Jdriscoll

Hi all. New XJ owner here, picked it up a few days ago. I am assuming it needs a head gasket and possibly a cylinder head. Compression check was good and held good compression but have not done an official leak down check, yet.
1994 Jeep XJ 152k miles
Overheats unless I run the heater.

the previous owner replaced radiator, water pump, thermostat, thermostat housing. temp sensor, electric fan, temp sensor on back of block, and a few hoses a few thousand miles ago but then let it sit because of the overheating.

I removed the thermostat to check that its operating and it is.
there is no coolant in the oil or oil in the coolant, no smoke out of the exhaust, no visual leaks.
Before I do a head gasket is there something else to check? I read that the transmission cooling could be the issue, is there a way to test that or bypass that so that I can check that off the list of potential root causes? What is the best way to check if the water pump is working well, just pull a line and make sure it flows?
I have looked at multiple diagrams of the coolant hose routing but nothing really shows the flow direction and I think that is part of the issue (could be wrong) but the lower/driver side coolant hose gets hot to touch, when shouldn't it be cool? and what I thought was the inlet to the radiator the top hose running off the thermostat housing into the radiator gets cool to the touch when I thought it would be Hot? This is leading me in the direction the waterpump is faulty or maybe they put on one that was the opposite direction of flow?

Sorry about the dumb questions that have been asked multiple times. But I have seriously searched all the overheat threads and I am still a little lost.

Thanks for the help and once I get this running I will have much better things to talk about and better questions to ask.

PatHenry

I would start with an oil analysis from Blackstone labs. While I was waiting on that, I'd just replace the water pump and flush the heck out of it while I was at it. The water pump is cheap enough, and a wear part that if I even question it - I want a new one in there.
When putting the WP back together (after running water through the block and radiator with a garden hose), I'd make sure that the coolant is a proper 50/50 mix and that the system is completely and properly burped. I'd also inspect the fan clutch if the overheating was more frequent during idle.

If it was still overheating after that, or if I got back bad news from the oil analysis - then I'd do the head if it is bad. In other words, I wouldn't just tear the head off unless I was sure I had to.

PatHenry

Just a couple additional thoughts.

Both the radiator hoses should be hot when the system is up to temp. If the upper hose (t-stat to rad) then suspect number 1 is a bad t-stat. Again, if in question I would replace it. Aftermarket ones can be flaky, so in your case, you should use a Mopar t-stat.

I don't think it's your case, but just something that came to mind - several years ago I was on a road trip (in a Jeep TJ) and all of a sudden the Jeep starts overheating. I pull over and the radiator is steaming.
Long story short, after a long fiasco and way too much $ spent I found myself on the side of the road, hundreds of miles from home removing the water pump in 90+ southern heat on the side of the road.
The water pump made no bearing noise, no leakage out the weep hole - what had happened was the plastic impeller had broken clean off inside and hence the pulley spun but the coolant wasn't flowing.
Thanks to the great highway people for the state of Maryland, I put a new pump in and made it home with no problem.