Improving the cooling on our TJs

Dggall

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Good point on the water pump. I am thinking maybe I should replace mine as well, I am already tgere
I am at 150k miles and am assuming that everything is original. Especially the way the radiator blew up.

Followed guidance on the forum and spent the bucks for Mopar. I have to say it was very tempting to go with something less expensive since there were so many options that were still rated fairly well and priced anywhere from 1/2 to 1/4 the price. I resisted and bit the bullet...

 
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TexasTJ2004

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I am at 150k miles and am assuming that everything is original. Especially the way the radiator blew up.

Followed guidance on the forum and spent the bucks for Mopar. I have to say it was very tempting to go with something less expensive since there were so many options that were still rated fairly well and priced anywhere from 1/2 to 1/4 the price. I resisted and bit the bullet...

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I can be cheap on Idle Air controller - I am running a 10$ piece from Amazon, because it is something that I can replace in 20 minutes. But water pump and thermostat and radiator are something that overheat the engine, if not working right. Also, it is pain to replace, so this is why Mopar on cooling components
 
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TexasTJ2004

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Mine used to run slightly hotter than 210 before I did a chemical flush and cleaned out the entire system. I ran it a total of 8 hours. Thermocure or Blue Devil is what I use.

I ran so far 3 flushed with BlueDevil, it didn’t seem to matter too much, as the color of the distilled water that I used in flush didn’t really change. I poured in Thermocure, and it it started to get black really fast. Are we expected to flush with thermocure till the coolant stays the same, and does not turn into dark black stinky thing?
 

cpwolf

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I ran so far 3 flushed with BlueDevil, it didn’t seem to matter too much, as the color of the distilled water that I used in flush didn’t really change. I poured in Thermocure, and it it started to get black really fast. Are we expected to flush with thermocure till the coolant stays the same, and does not turn into dark black stinky thing?

This is the water after Thermocure. Left after first, and so on. Far right is probably good to go, but I drained one more and didn’t take a pic, was slightly clearer.


F32326E0-0497-478B-9BEE-2E2E600AA33D.jpeg
 

cpwolf

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I just ran thermocouple for like 20 minutes, to burp the air.
And this is what I get:

View attachment 347089

I ran thermocouple for 1 1/2 days. Not saying I did it right, but this stuff reacts to rust. I’ve cleaned a lot of parts and BBQ smoker parts with Vinegar, and a few others that are more expensive, it takes 12 hours to a couple days to get a serious cleaning. I thought the bottle said 3 hours up to 3 days, but I don’t recall exactly. It obviously got some, but it was obvious to me that the stuff worked on it after a few days. Stunk to high heaven as well.
 
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TexasTJ2004

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I ran thermocouple for 1 1/2 days. Not saying I did it right, but this stuff reacts to rust. I’ve cleaned a lot of parts and BBQ smoker parts with Vinegar, and a few others that are more expensive, it takes 12 hours to a couple days to get a serious cleaning. I thought the bottle said 3 hours up to 3 days, but I don’t recall exactly. It obviously got some, but it was obvious to me that the stuff worked on it after a few days. Stunk to high heaven as well.
I will run every lap for couple of days, with at least 3 hours of driving in total.
Plan to drain the entire at the end of the process. Now when I did it one time, I can do it again.
The only problem with draining the block is the sudden shower that one gets when the plug finally comes out.
 

Ericshere03

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I will run every lap for couple of days, with at least 3 hours of driving in total.
Plan to drain the entire at the end of the process. Now when I did it one time, I can do it again.
The only problem with draining the block is the sudden shower that one gets when the plug finally comes out.

You found a drain plug on the block ??? I didn’t think we had those …
 

cpwolf

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You found a drain plug on the block ??? I didn’t think we had those …

Look between the Cats, it’s on the block, a square 8mm plug. I actually got to the point where it wasn’t that bad really. I wasn’t putting. Any tape on it until the last time, and I put sealant putty.
 
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TexasTJ2004

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I think that we have to use the block drain in order to remove all leftovers from the thermocure. Draining through the radiator does not really do the job, as it drains only like 60% of total in best case.
You need to get the 8mm square from Amazon, CTA Tools 2036 8mm Hex Drain Plug Wrench https://a.co/d/b4IWPrM.
Lessons learned - in order to break it lose you need to crawl under the Jeep, but when it is almost open, try to open it by holding the wrench with extender by hand. You don’t want to be under waterfall of stinky thermocure.

589DD71D-D71C-4D54-BB87-A28CE0A0672A.jpeg
 
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TexasTJ2004

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I think that I have found the root cause for my overheat problems.
I bought this kit for 90$, OIMERRY 28PCS Universal Radiator Pressure Tester for Vehicles, Vacuum Type Coolant System Pressure Leak Tester Kit https://a.co/d/5d7w88n

And ran positive pressure test. At around 13 PSI, I see that the coolant started to leak from the heater core.
I am currently running distilled water with thermocure, so my cabin stinks of thermocure, with this thing mainly pouring under the Jeep from the tube that is supposed to be for condensed water from AC.
With leaking heater core, it is not able to build proper pressure of coolant, and this brings air into the system.
I wish I had run this test before I replaced the fan clutch, before replacing a thermostat and before ordering a new Mopar radiator.

My lessons learned - always run exhaust in coolant (which I didn’t run yet) and positive pressure test. If any of these fails, no point in replacing half of the cooling system.
 

DEValken

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Good lesson to learn, and you have new good quality parts on your rig. If they last as long as the original you shouldn't have to worry about them again.

Bonus, you also have a good backup radiator, water pump and thermostat to stick on the shelf...
 
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MountaineerTom

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I think that I have found the root cause for my overheat problems.
I bought this kit for 90$, OIMERRY 28PCS Universal Radiator Pressure Tester for Vehicles, Vacuum Type Coolant System Pressure Leak Tester Kit https://a.co/d/5d7w88n

And ran positive pressure test. At around 13 PSI, I see that the coolant started to leak from the heater core.
I am currently running distilled water with thermocure, so my cabin stinks of thermocure, with this thing mainly pouring under the Jeep from the tube that is supposed to be for condensed water from AC.
With leaking heater core, it is not able to build proper pressure of coolant, and this brings air into the system.
I wish I had run this test before I replaced the fan clutch, before replacing a thermostat and before ordering a new Mopar radiator.

My lessons learned - always run exhaust in coolant (which I didn’t run yet) and positive pressure test. If any of these fails, no point in replacing half of the cooling system.

I replaced mine a few years back. Wasn’t to difficult, just time consuming.

https://wranglertjforum.com/threads/another-heater-core-replacement-and-a-c-evap-core.15568/

There are some other write ups for it on this site as well.
 
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TexasTJ2004

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TexasTJ2004

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Short term, I did this. Dorman bypass, I had the same issue, but I went ahead and replaced everything and did this, heater core is on the bench waiting for it not to be 105+ in my garage.

Dorman 626-001 Engine Heater Core Bypass Kit https://a.co/d/a4rthSz

Already ordered this part. I will not need the heating till like November anyway.
 

Ericshere03

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I think that we have to use the block drain in order to remove all leftovers from the thermocure. Draining through the radiator does not really do the job, as it drains only like 60% of total in best case.
You need to get the 8mm square from Amazon, CTA Tools 2036 8mm Hex Drain Plug Wrench https://a.co/d/b4IWPrM.
Lessons learned - in order to break it lose you need to crawl under the Jeep, but when it is almost open, try to open it by holding the wrench with extender by hand. You don’t want to be under waterfall of stinky thermocure.

View attachment 347216

I feel so stupid, all these years … I always pop these suckers out on other engines, I’ve seen all sorts of mysterious junk come out. But I like to replace the plug with brass. Some people use a radiator petcock, but that’s risky and brass will never seize.

For the TJ’s. To fully flush the system I run the engine with the upper radiator hose off, thermostat removed, garden hose in the top of the radiator going full blast. Then I run the engine. I’ll let it go till that water runs totally clear. Then I’ll remove the heater core hose at the thermostat housing and run the hose through there.

This time around I’ll remove that drain plug and do it the right way.