Is this vehicle LHD? Has you scanned the radiator with an IR thermometer?

 

Both the old and new hose didn't come with springs. I thought that could've been the problem too. So no, the one I replaced doesn't have a spring in it

 

An intense raspberry thermometer? Never heard of such a thing.

It is an 80 degree day, you are not loaded and not towing.

If your aw4 is cruising down a flat highway at 65 with a locked tq converter I don't think that should be introducing significant heat to the cooling system even if the trans if half dead. Again same driving conditions, your fans could be non existent and the cooling system is being feed by the vehicle moving through the air to stay in the acceptable heat range.

If this were my problem I would start looking at a restriction in the radiator, hoses included.

 

This hasnt been throw in there, but verify the temp with a second temp guage. My stock guage reads 20 degrees hotter than my autometer guage.

Fan clutch, water pump, thermostat, complete cooling and radiator flush (or just buy a new OEM one at $150)

 

Assuming you have swapped the thermostat, I'm going to go with radiator or flow system on this one. At highway speed, you should be moving enough air over the radiator even without the fans on to keep the engine cool.

(I used to have a Yota' 4 banger that with a misaligned alternator that caused it to blow fan belts on a regular basis that I could drive down the freeway at 70 no problem. Soon as I would take an exit, though, I would have to pull over and slap on a new fan belt).

The fact that you are NOT, says that either A) the radiator is not getting the coolant cooled down or B) that cooled coolant is NOT getting into the block.

REAL test would be to start it up in your driveway and just let it idle for 20 minutes. Does it get too hot? If not, THEN it's time to start looking at induced heat sources; drive it around town at LOW speeds (35ish). Does it get too hot? If not, THEN it is probably time to look at the transmission.

 

Forget the spring. It's not necessary. The spring was in the factory hose because of the way they filled the system at the factory. To efficiently fill it while preventing air bubbles from entering the system and to check for leaks, they pulled a vacuum on the coolant system, then let the vacuum pull in the coolant. The spring was in the lower hose to keep it from collapsing under that vacuum.

If you have a problem in your cooling system that is causing that much vacuum, a spring in your lower hose isn't going to fix it.

 

No, silly. It's an Isabella Rossellini thermometer.

 

I'm not saying use the spring in the normal sense that it is recommended/used. I am recommending that it be put in because it's easy and cheap. If the problem resolves than the radiator can be suspect for restriction. Yes the hot side is pressurised to that of the radiator cap, I know. The coolant in the cold side ( bottom) is being pulled into the pump possibly after a restriction we don't know yet. The spring at this point is a diagnostic tool.

 

It's not a positive displacement pump, engine heat= thermal expansion to pressurize the cooling system & raise the boiling point of the coolant.

 

Are you implying that I think a water pump is what creates a pressurised cooling system in a 4.0? That is slightly offensive.

 

After thinking it over a bit, I guess my last option on the cooling system is to replace the radiator. If that's not it, then I guess ill have to start looking elsewhere besides the cooling system. This probably won't be until probably a week or two sense I wont be back home until then.

 

I am no expert, but we have dealt with cooling issues on both our XJ's. Often the culprit on them were the Water pump (are you sure it is the right one? Some are look right but can be incorrect), fan clutch (cheap enough to replace to insure it's not the issue) or a stuck thermostat. I also had an issue with my auxiliary fan wasn't coming on. So I wired mine so that it is on it's own switch.
If you have no leaks and have done a flush on it and have good flow through it I doubt the radiator is the issue. My bet is on the fan clutch. I hope you find the culprit.

 

The new water pump we installed is the right one, so is the new thermostat. Didn't have a thermostat when I bought the jeep. I'm pretty sure the fans are good, and like mentioned before, on the highway the fans don't really play a big role. And when I'm driving say 50mph or less, it doesn't heat up. So that's a big indicator that the fans are ok. I guess the last thing to do is flushing it really good. When we replaced the pump we didn't really flush it, just poured new coolant in it. So that might be what I do next.

 

Does anyone have a method for testing the radiator to make sure its doing its job before I go buy a new one?

 

I would do a flush on the radiator, so many people don't know that tap water is the worst thing to put into their coolant system. Over time it rust and will gum up everything. I would still check that thermostat again they are cheap enough and drill a pin hole in it to insure that the air will be purged out of the system. the one thing about building up our rigs is it adds to the strain on the engine witch increases the heat it generates. I hope you get to the bottom of this and please post what ends up fixing the problem.