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Improving the cooling on our TJs

Artsifrtsi

I just wanna go wheeling...
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I think that the best test is try to run the jeep w/o thermostat, and see whether it can cool itself just fine. If it does, then the thermostat is the problem.

No, the cooling system needs that restriction to allow the correct surface contact to the radiator coils.
 

mattyice2

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Jan 21, 2018
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York County, PA, United States
I've noticed that mine runs a little over 210 when idling in this 90-degree hell heat wave. I worry too, but I think we're just over worrying. I remember hearing something that the AC can overheat the engine. So maybe turn the AC off if you're idling for a long time.
 
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TexasTJ2004

I love my TJ
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I've noticed that mine runs a little over 210 when idling in this 90-degree hell heat wave. I worry too, but I think we're just over worrying. I remember hearing something that the AC can overheat the engine. So maybe turn the AC off if you're idling for a long time.
This is where it reaches in idle with AC on.
AC off improves the situation.
If I activate the heating in t he cabin full blast, it puts the temperature into the normal range.

C21CA5F7-5664-4344-AAA0-21503F3D847D.jpeg
 

Irun

What I want isn't as important as what I need!
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This is where it reaches in idle with AC on.
AC off improves the situation.
If I activate the heating in t he cabin full blast, it puts the temperature into the normal range.

View attachment 345090

As was said, this is perfectly normal. I've cleaned my cooling system, used a Mopar radiator and waterpump, and replaced the fan clutch and all other cooling system parts. In 97 degree heat, bumper to bumper traffic, and the A/C blasting, that's where mine sits. I'm not in the least bit worried!
 
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TexasTJ2004

I love my TJ
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I've noticed that mine runs a little over 210 when idling in this 90-degree hell heat wave. I worry too, but I think we're just over worrying. I remember hearing something that the AC can overheat the engine. So maybe turn the AC off if you're idling for a long time.

AC evap coil is much hotter than radiator. It definitely adds to the problem.
I am putting in a cheap autozone thermostat (mopar one will arrive like end of month only, autozone one should) and making flush with BlueDevil tonight, I will update whether it reduces the temperatures.
My entire problem started a week ago, when I finally fixed my AC, got it fully charged, working by the spec (low/hi pressure lines consistent with radiator ambient temperature and cabin air vent outlet temperature in recirc with 100% cabin fan and max cooling). Before that it was not getting too hot. Was slightly on the hot side, but not too hot.
 
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TexasTJ2004

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If you go into the FSM (https://wranglertjforum.com/threads...ice-manuals-fsm-technical-documentation.4618/), it lists the expected AC performance.
I am using manifold to measure AC hi and low pressure, thermometer to measure ambient air inlet on radiator grill, and small autozone thermometer for AC vent outlet.
I have verified that when engine is not too hot (right on spot with 210F or lower), the AC hits the precise performance metrics.
The moment that it starts getting hotter, it is unable to hit the relevant metrics.
Checking the pressure in the manifold, I see that we go into the territory of low side pressure as expected, and high side pressure too high (out of spec).
I have excluded the overcharging, as i know the quantity of freon that I have added, and I have been tracking the pressures when adding freon.

Judging from the FSM's definition for AC performance, the cooling system is not operating as expected in the attached picture, as it is unable to move away the heat from evaporator.
The fact that a lot of folks have the problem, does not make the problem to be non issue.


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C21CA5F7-5664-4344-AAA0-21503F3D847D.jpeg
 
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TNHEADDUCK

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Dec 3, 2015
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Music City USA
Hook up a quality manual temp gauge to your cooling system and check it against your factory gauge, But like you have been told already you are trying to fix a problem that doesn't exist as far as running too warm. JMO
 
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TexasTJ2004

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No, the cooling system needs that restriction to allow the correct surface contact to the radiator coils.

Right now I am doing a flush. For sake of experiment, I have removed the thermostat, and running distilled water only. Need to run it like 10 minutes for flush purposes. The temperature does not even cross 150 of thermostat is removed.
My understanding from this is that the thermostat was messed up.
 
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TexasTJ2004

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Right now I am doing a flush. For sake of experiment, I have removed the thermostat, and running distilled water only. Need to run it like 10 minutes for flush purposes. The temperature does not even cross 150 of thermostat is removed.
My understanding from this is that the thermostat was messed up.

69A8DEFC-2F82-4142-979A-E8F852E3B515.jpeg
 
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TexasTJ2004

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And now,. With full AC on, blasting 100%, max cold, hood open, the AC temperature is in the spec range, as cold as it should be, hi and low pressure are where they should be.
If with removed thermostat this thing can cool itself inside my garage ( the garage is open, but it is still very hot over here), maintain the AC temperature by the spec, and also the engine temperature under 210F, this definitely points to thermostat.

0E77A73A-7691-477F-B72D-16FBA732FA7C.jpeg


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DEC68E1A-4972-4C3E-9017-E4A0F0C18976.jpeg
 

mrblaine

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And now,. With full AC on, blasting 100%, max cold, hood open, the AC temperature is in the spec range, as cold as it should be, hi and low pressure are where they should be.
If with removed thermostat this thing can cool itself inside my garage ( the garage is open, but it is still very hot over here), maintain the AC temperature by the spec, and also the engine temperature under 210F, this definitely points to thermostat.

View attachment 345193

View attachment 345194

View attachment 345195

Your issue is not the thermostat. You can put a brand new Mopar in with a drilled hole to bleed the air out and you will still have the same issues. You need the flush done to clean out the block and remove the scale and rust to allow more efficient transfer of heat into the coolant. The second thing kicking your ass is that piece of shit radiator. Fix both of those and you'll be much happier.
 
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TexasTJ2004

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Your issue is not the thermostat. You can put a brand new Mopar in with a drilled hole to bleed the air out and you will still have the same issues. You need the flush done to clean out the block and remove the scale and rust to allow more efficient transfer of heat into the coolant. The second thing kicking your ass is that piece of shit radiator. Fix both of those and you'll be much happier.

Thanks a lot for your insight. I am in the middle of triple Blue Devil flush. That should cover the flush part.
As for the radiator, I have just found out that Mopar no longer sells radiators for TJ and I will have to research which radiator to put in.
 

cpwolf

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0E4520A6-3FFE-42FC-9C38-11495B167486.png

I’m going to be a jerk here. One site or two listing “discontinued” doesn’t mean they aren’t out there. Literally Amazon has a listing with 1 left in stock right now.

You have to search a little. I’m sure eBay has some, I’m not going to look there too, but if you want your Jeep to work right, I’d get on it asap.
 

DB04RedJeep

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As @cpwolf said they are available. Ordered one on Tuesday night from Amazon (manual transmission) and it was at my door Friday mid day in a factory unopened box brand new.
 

MountaineerTom

LJ Enthusiast, Retired USAF Weapons Loader
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And now,. With full AC on, blasting 100%, max cold, hood open, the AC temperature is in the spec range, as cold as it should be, hi and low pressure are where they should be.
If with removed thermostat this thing can cool itself inside my garage ( the garage is open, but it is still very hot over here), maintain the AC temperature by the spec, and also the engine temperature under 210F, this definitely points to thermostat.

View attachment 345193

View attachment 345194

View attachment 345195

Damn, that's some cold A/C! I can never get mine below 57-58* this time of year,