I'm curious, what is considered "overheating" on a 4.0? Obviously above 210 is "hot" but when does that turn into overheating?

I don't know if it was the fact is was a tiny bit cooler today or that the flush had some affect already, it constantly ran a cooler than the last week, I still had my AC on and my new shroud isn't here yet(went to junk yard AND NOT A SINGAL XJ HAD ONE) but it ran a bit cooler.
I'm debating replacing the radiator next weekend as I got Saturday off.

Edit: I have to go to a wedding. Sigh. Never mind.

I have a similar issue with my xj with it running hot especially in the 104 degree weather in California right now. I was talking to my mechanic after we finished fixing my AC system about he cooling system and he said it gets hot easily because the radiator isn't strong enough for the heat the I-6 produces. My cooling is in tip top shape but still gets hot easily. I will buy a new radiator and stock temp t-stat when I get my muffler replaced (it's broken) and have the money.

After a good flush, new antifreeze and a shroud this is where it sits now, barely climes over 210 in hot traffic with AC on, I'm satisfied for now.

Exactly like my '96 temp runs. Looks like you got it fixed.

Lucky. I was helping my boss deliver equipment to his house today and he switched to his corvette to drive back to work and the plan was for me to follow him but I nearly over heated just trying to keep him in sight. I didn't know my way around the area and my phone shut down because it was too hot so I couldn't use it for directions back if I lost him lol:icon_rolleyes:

IMO 225 is hot as balls, and 240 is an overheat condition (probably 230 with an 0331 head). Really, if it starts creeping much above 210 I usually try and do something about it so the situation does not get much worse. Even stuck on 25 in the middle of the day I still sit right around 210 without having to do anything special - no A/C though.

Depending on circumstances, I won't actually shut the motor off if it gets that hot but I will stop, pop the hood open, and hold it at 2000 rpm or something to get air through the rad (not only airflow, but coolant flow as well)
Completely dependent on circumstances though, if its about the blow the radiator cap off, just shut the damn thing down. I also have a manual trans so its easy to just pop it in neutral and hold the RPM's at 1500 or so to keep good airflow

But I just prefer to play it safe and not waste a day swapping heads/motors in the worst case

EDIT:
I also was at the JY this weekend, only 3 97+ XJ's, all picked pretty clean :(
Needed an e-fan, got new hatch struts instead so not a total wash

I'm just glad the flush fixed it, today it hit 100 at my work and house, sitting in it idling at lunch with the AC on it maxed out at 217, which I was okay with considering it was 100 out. Agree that anything over 220 is too hot. I didn't like it. 240 was when I worked it hard climbing I-70 with the AC on, I was stress testing it, and it failed. I think this rad will be fine for now. It's doing its job and I'm putting a tranny cooler on this week to keep it cool when I wheel and I do occasional towing.

Should I cut out the rad cooler all together or just loop in the external cooler?

Not holding it against you - it's not like pulling over on I70 is an easy thing to do (when traffic is flying by you and truckers are foot-to-the floor to make it up the hill).

Trans cooler is a solid idea. Don't waste time with the tube and fin ones though, get a plate and fin cooler - much more efficient

It hit 240 but that was at the top of the mountain so wasn't worth pulling over at that point, on the down hill it fell from 240 all the way down to 170 and the thermostat closed. So it cooled off very quickly.

Edit: I got a plate and fun cooler.

Thread revival time yay! *sarcasm*
She's once again running hot. At this point I'm gonna just replace the radiator and be done with it. I'd estimate it has a 20% antifreeze and 80% water mix right now. That wouldn't cause it to run hot would it?
I have plenty of air flow and I doubt my little tranny cooler blocks enough air to cause it to run hot. But who knows. It's in front of the e fan so I don't see it cutting off the clutch ones flow. It has a shroud and both fans work. Radiator and water pump maybe? I don't know but it's annoying me.