The OP was having issues before the mods so implying just going back to OEM overheating will go away is doing a disservice.
That said I agree the aftermarket mickey mouse horseshit doesn't help but the OP has an issue(s) in the system.
^^^^^^
You need to be a little more specific on your over heating issue.
On the trail only? That indicates to me you are going slow, idling, back to slow, idling...etc.
Does it over heat no matter what and where? Highway...town...trail no matter.
Always eventually heating up too much..???
Are you losing any coolant whatsoever?
A quick radiator cap test you can do is look at your over flow before a cold start.
Then get it to your 214° or so. Check your overflow. It should be at a different level than your cold start.
If it's the same level as to when you started cold...your cap is junk. Now you might have other issues as well but your cap is definitely not behaving as it should.
Again though more specifics on your issues will help a great deal.
Start with your overflow observation.
Good luck.
First I will apologize for this is a long read but trying to fill in the blanks as requested and answer the questions.
I don’t drive long distance with the Jeep very often, the Jeep is primarily used to get to and from the trail and then trail use most of the day.
So for we have only made one trip of any distance from Wickenburg to Surprise and back. It did not overheat or peg the gauge during the trip but it did reach about 214 on my gauge.
Most of our trips consist of 10-15 miles out to the trails and then 20-50 or more miles off road on the trails. Most trails or fairly tame rarely anything of the technical type. Even though we are well equipped I don’t get over the top because we are out prospecting and always alone and a lot of times no cell service. Other than a trip to the one of the local stores or to grab dinner that is our trip description.
Last winter when we came out we had some heat issues heading up the mountain towards Yarnel, same problem the gauge pegged out and the computer evidently doesn’t like it the Jeep will barely run until it cools down. This has happened twice this year. Last year I thought I had a bad sending unit and or possibly a bad thermostat when this happened, I replaced both and still had issues running hotter than it should. I purchased an infrared thermometer to see if my gauge was close or way off. At the thermostat housing with the engine at 214 per my gauge I was getting a reading with the infrared very close to my gauge so I am presuming that my gauge is relatively close. Last year on our last day on the trail my AC locked up or so we thought and this made me think maybe the compressor was the issue. (The fan belt squealed and I smelled Freon.) But after returning home the AC worked normal but my engine temps were still to high for my liking. We flushed the system thoroughly including running a hot power washer through the block afterwards to flush the block. We installed a new water pump not rebuilt, still the same runs about 210-214 at home based on gauge and two different thermal heat guns.
This trip, it starts out fine locally but then after a few miles the temps climb up to 210-214 or so with or without the AC even though with AC it stays around 214 or so. When we get on the trails it stays around the 214 with or without AC. With the AC off it takes longer for the temps to reach 210 plus than with it on especially when air temps are in the 90*s.
Every time it has pegged out the gauge the AC has been on and we were running in lower gears and in tighter trails.
To answer the question regarding coolant level. So for it has never lost any and the reservoir seems to stay the same. No boil overs like you would normally expect. All seems to be the same regardless of what size thermostat I run.
Yesterday I removed the stat drained the system and flushed until clear of coolant. Poured a bottle of flush in and drove it around town for a while. Yesterday was only about 80* and the Jeep still was running 200 - 210 or so without the AC on and no stat. When running the AC it was about the same but climbed quicker. I did have windows open and heat on for a while trying to flush the heating system too. When returning to my home base I drained and flushed the system, nothing really came out except a slight tenting color of antifreeze. So at this point I feel the system is as clean as it can be made. Inside of radiator looks like new same with block as best I can tell looking into where the stat goes.
As an experiment I removed the valve in the thermostat put it back in with fresh 50/50 coolant and a bottle of Purple Ice to see how my day goes. I know these new engines don’t like it when they run to cool but so for even wide open doesn’t matter it still gets to 214.
I didn’t want to run without a stat because I know you need some restriction so the coolant can absorb the engine heat as it passes through the block that is my reason for removing the valve and putting the stat in for restriction. Will see and don’t think it is the answer.
This is not something I would normally do but I figured I would experiment with this idea sense nothing normal has worked, I do have a spare stat, gasket, and coolant if needed.
So for there has not been any noticeable coolant loss or level change in the reservoir even when the gauge spiked but I can tell you as soon as I opened the hood it was obvious that it was extremely hot. I let run at a fast idle with the AC off and the temps will start to drop them allow it to idle and cool down. I also trickled water down the radiator and it seem to bring the temps down quicker.
I plan to run by NAPA today and pick up a new radiator cap and another stat and gasket this morning. The spare I have now is a Murray from O'Rielly and their gaskets aren’t very good.
Hopefully the cap will help and I can put a proper stat back in. I called my shop back home and having my mechanic box up my fan and shroud and ship it to me today so I can put it back on if needed.
