Need advice from 110 degree plus climate TJ owners

If your system is in good condition, but is still getting warm you could install another heat exchanger. I know in some of the racing circles they run smaller radiators or even heater cores underneath or behind the bumper to add system capacity as well as cooler surface area. I have done a few on some turbo gen 2 Vipers. The 80's Chevy Suburban heater cores are cheap and easy to install with a small fan. Hood vents can work, but I have seen a few examples where a hood wasn't vented correctly and it caused pressure under the hood at speed. That can actually reduce the flow through the cooling stack and make it heat up. Also I wouldn't loose too much sleep over the 0331 head. I have been very mean to mine and it's still holding up. I had it off a while back to do the lifters, and had the machine shop check it. It was perfect and went back into service.
 
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Too darn hot in the garage to finish installing my radiator.
TheBoogieman said:
It's not the heat, it's the humidity. ;)
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11% humidity. I am dying. Muggy as all get out.
temp001.jpg
 
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mousehunter said:
stupid question - tires and gear ratio? Lots of the coolant system are linked to the engines RPM - I might be wrong, but I think we have a belt driven radiator fan and gear driven water and oil pumps). If you have the wrong gears, the engine is working hard at low RPM - all the heat, but less cooling. My gears are very wrong. I think I saw a a 5-10 degree difference just by turning overdrive off (which puts the gears about where they should be).

As for interior temps. not sure about a solution. I am going to be putting on a slightly insulated hard top with tinted windows. I am also adding a roof platform that will significantly shade the top of the roof. Not sure if it will help much or not. I do know in Texas, a sun roof turns your interior in to a easy bake oven. Fast backs are probably worse - more glass lets more of the oven light in. (I mentioned fast backs, because while I like the looks of the tappered soft tops, I bet they are warm).
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My highest coolant temp (just to the right of the zero for 210) was recorded on the freeway at 65mph with the AC on. Engine rpm is 2300 ish at that speed. Gears are 3.73. nv3550 5speed manual. 30x9.5 tires. Literally all stock options. This jeep is as close to stock as it can get aside from my KC lights. I run a soft top year around. Full doors. Inside temps arent an issue with the AC on. But the coolant temp with the AC on, is quite a bit higher.
 
Jezza said:
If your system is in good condition, but is still getting warm you could install another heat exchanger. I know in some of the racing circles they run smaller radiators or even heater cores underneath or behind the bumper to add system capacity as well as cooler surface area. I have done a few on some turbo gen 2 Vipers. The 80's Chevy Suburban heater cores are cheap and easy to install with a small fan. Hood vents can work, but I have seen a few examples where a hood wasn't vented correctly and it caused pressure under the hood at speed. That can actually reduce the flow through the cooling stack and make it heat up. Also I wouldn't loose too much sleep over the 0331 head. I have been very mean to mine and it's still holding up. I had it off a while back to do the lifters, and had the machine shop check it. It was perfect and went back into service.
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I appreciate the ideas. If I don't find any issues and still have higher temps than I would like, I will look into this. Glad to hear that you have had decent luck with your cyl head. So far so good with mine. I think... Lol. 200k on this jeep. I think it would have gone by now if it was going to.
 
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RINC said:
Too darn hot in the garage to finish installing my radiator.


11% humidity. I am dying. Muggy as all get out.
View attachment 336647
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Sorry for you. Not the best time of year to be having to work on your jeep. If it makes you feel any better about your situation, I installed mine in direct sunlight in my side yard in may. Was only 98° though.
 
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Have you verified your ac condenser it clean and free from obstructions?

If you can not run ac due to engine temps climbing then your cooling system is having an issue or is inadequate.
 
looks like I'm a little late to the party, but heres what I wind up doing to fight this ridiculous Texas heat (104*RN)

First step get yourself something to read the actual numerical output of the temp gauge, not the stupid idiot light excuse for a needle on the dash, but an actual gauge. I use an Ultragauge one of the best investments ever, plugs into the OBD2 and shows what the computer sees, super cheap and simple and waaay better than the wireless dongle and app I was using before

(you can see it in the top left of this photo - engine was cold at the time)
E167A776-F446-429D-9D2F-6CD852EA6E03_1_105_c.jpeg


I then replaced the whole cooling system, using a HD fan clutch and all MOPAR parts. Make sure to replace your rad. cap and thermostat housing!!!!! my housing was cracked so slightly I hadn't noticed and led to VERY slight leak and overheating at idle.

if you are overheating going down the road, you have a different problem but for me I couldn't pull enough air through the rad at idle to keep her below 220* (whereI start to get nervous) so I wound up installing a AUX. electric cooling fan this was before I found the crack in my thermostat housing and may not have been ultimately necessary but has been absolutely dead nuts reliable thought the summer. I can not get this thing to go above 215 no matter how long I sit in traffic, fan comes on and cools her right back down to 200 if I leave the fan on she'll stay right on thermostat at 195.

1FF9CEEE-AE9A-4BB7-8515-765126D316F8_1_105_c.jpeg
 
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Gollywomper said:
Have you verified your ac condenser it clean and free from obstructions?

If you can not run ac due to engine temps climbing then your cooling system is having an issue or is inadequate.
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Yes, I have cleaned everything. Made sure of that yesterday. I am going for my test spin with the odb2 reader right now. Peak ambient temp of today. It's 110 right now. I will update the thread with screenshots of coolant temps after I get back.
 
Alright y'all. It's bad. This is the last temp I recorded after idling for 5 minutes in the driveway after the drive.

Screenshot_20220612-161002.png

This is the last temp I recorded at highway speed after traveling about two miles down the freeway.
Screenshot_20220612-155800.png

Once it's above 235, it won't come back down under that without turning the ac off. Even on the highway. That said, it didn't seem to want to go above 250. So it's not like it's running away rapidly.
 
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Sadly, I am no mechanic. Over the years I have had various trouble with cooling systems. I've had badly calibrated thermostats (you can test the calibration - that one really frustrated me, it was a new thermostat), clogged cores, clogged fins, failing fan clutch, and then I have had some I am still trying to figure out. It was really fun when several of those happened at the same time (blew the radiator, water pump, oil pump and pmc in 2 weeks). In all fairness, all of those were pretty long ago-knock on wood.
 
RINC said:
Too darn hot in the garage to finish installing my radiator.


11% humidity. I am dying. Muggy as all get out.
View attachment 336647
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Case in point - that's a 70 degree wet bulb temp and would be felt as more comfortable than the 95F/60% humidity that we had yesterday - a WB of 83, because evaporation of sweat is more effective.

Jeep will much prefer the 95F/60RH though.
 
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freedom_in_4low said:
Case in point - that's a 70 degree wet bulb temp and would be felt as more comfortable than the 95F/60% humidity that we had yesterday - a WB of 83, because evaporation of sweat is more effective.

Jeep will much prefer the 95F/60RH though.
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idk what this "wet bulb" temp is you're talking about. today is plenty hot enough to get my balls wet.
 
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iamloganjames said:
Alright y'all. It's bad. This is the last temp I recorded after idling for 5 minutes in the driveway after the drive.

View attachment 336670
This is the last temp I recorded at highway speed after traveling about two miles down the freeway.
View attachment 336671
Once it's above 235, it won't come back down under that without turning the ac off. Even on the highway. That said, it didn't seem to want to go above 250. So it's not like it's running away rapidly.
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Start with the basics: pressure test system and cap, test coolant for exhaust gases. If you still have the original clutch, install and see if there’s any difference.
 
iamloganjames said:
Quick question for y'all. Is this too loose for my fan clutch to be after a 250° coolant temp drive? Filmed this 10 min after getting back. It does not freewheel at all. Just relatively easy to turn slowly with one finger.
https://drive.google.com/file/d/1xlVMgD2N5Tlznx768uAutX7OkP5AfEPu/view?usp=drivesdk
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Looks fine to me, those temps are really high though


I hate to be this person, but how much do we trust the actual sensor, do you have any other symptoms of heat, does the engine feel abnormally hot? At temps that high running down the free way I would begin to question the sensor, maybe try another MOPAR one or even just a laser heat gun.

At those speeds it’s not your fan, could be blocked airflow through the rad. Or maybe a really small leak/ air bubble.
 
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