2004 TJ overheating problem

Tj jeep

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Cape Coral Fl
I have a 2004 wrangler 4.0 automatic I’ve had an overheating problem I’ve put new water pump new thermostat new 3core aluminum radiator I’ve bypassed heater core to see if that was an issue found out have a small leak. I’ve flushed out radiator engine and heater core and put new antifreeze back in if I sit at idle temp goes up to 212 215 and will stay there tell I start driving and when I get up to higher speed it will get hotter then I will turn heater on and it will go back to 212 degrees. I’ve had this issue for a few years now I can only drive it short distance. The only thing that I haven’t replaced is the fan clutch or would you recommend removing the fan and putting electric on
 
The only thing that I haven’t replaced is the fan clutch or would you recommend removing the fan and putting electric on

No, putting an electric fan on would be a horrible, stupid decision. That will likely just lead to more issues.

That 3-core "aluminum radiator" is probably part of the issue. Those things are known to be problematic, so I can't rule that out as part of the issue. You should be using a genuine OE Mopar radiator in all honesty.

Still, running at those temps isn't abnormal. What is the highest it gets up to?

Also, have you checked the radiator when the engine is cool to make sure it's full?
 
No, putting an electric fan on would be a horrible, stupid decision. That will likely just lead to more issues.

That 3-core "aluminum radiator" is probably part of the issue. Those things are known to be problematic, so I can't rule that out as part of the issue. You should be using a genuine OE Mopar radiator in all honesty.

Still, running at those temps isn't abnormal. What is the highest it gets up to?

Also, have you checked the radiator when the engine is cool to make sure it's full?
The temp gets up to red line and I’m losing fluid back in reservoir I’ve also put on a new radiator cap.. I put the aluminum radiator in cause the original radiator I thought was bad cause I was over heating then
 
I would put an oem t-stat in first then burp the system and make sure there is no air at all I’m it. You can use something like this EPAuto Spill Proof Radiator Coolant Filling Funnel Kit https://www.amazon.com/dp/B01I40ZQWE/?tag=wranglerorg-20 to burp the air out. It sounds your over heating wile driving and not at idle so it’s not the fan. I would check the inlet and outlet temps of your radiator. Just to make sure it’s cooling properly.
 
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I have a Mopar water pump, stock 195 thermostat, and stock Mopar radiator and never hit 205 even with long highway drives. It’s always below the middle. I’d suspect radiator as others have said. Mopar equipment is cheaper and lasts 100k miles

You can burp your system by having the cap off your radiator and running the vehicle. You’ll need to run it until the thermostat opens. You’ll see air bubbles coming to the surface of the radiator. Add fluid as needed to reservoir and radiator. You can also squeeze the upper radiator hose to force air out. This won’t get everything out, but should get any large pockets out of the system.

Are you losing coolant or have coolant in your oil? Your heater core is leaking so you bypassed it?
 
I have a Mopar water pump, stock 195 thermostat, and stock Mopar radiator and never hit 205 even with long highway drives. It’s always below the middle. I’d suspect radiator as others have said. Mopar equipment is cheaper and lasts 100k miles

You can burp your system by having the cap off your radiator and running the vehicle. You’ll need to run it until the thermostat opens. You’ll see air bubbles coming to the surface of the radiator. Add fluid as needed to reservoir and radiator. You can also squeeze the upper radiator hose to force air out. This won’t get everything out, but should get any large pockets out of the system.

Are you losing coolant or have coolant in your oil? Your heater core is leaking so you bypassed it?
The radiator is new 3 core aluminum new water pump new thermostat 160 degrees new hoses and new radiator cap I let it burp for 45 minutes with heater on i checked the clutch fan it speeds up when accelerate and slow down when letting off I do have small leak in heater core.... at idle it stays at 210 once I put the cap on and drive it it goes up to in temp drive about 10 miles it goes up to 240 and over... I’ve checked oil to see if any radiator fluid is on dip stick and no there’s not... I’ve checked to see if there any coming out of exhaust no smell no moisture coming out.... I took the OEM radiator out cause it was bad and that’s when I replaced water pump and put a 195 thermostat in..This has been an on going issue the last three years it wasn’t as bad through the couple years but now I can’t go over 10 miles
 
The radiator is new 3 core aluminum new water pump new thermostat 160 degrees new hoses and new radiator cap I let it burp for 45 minutes with heater on i checked the clutch fan it speeds up when accelerate and slow down when letting off I do have small leak in heater core.... at idle it stays at 210 once I put the cap on and drive it it goes up to in temp drive about 10 miles it goes up to 240 and over... I’ve checked oil to see if any radiator fluid is on dip stick and no there’s not... I’ve checked to see if there any coming out of exhaust no smell no moisture coming out.... I took the OEM radiator out cause it was bad and that’s when I replaced water pump and put a 195 thermostat in..This has been an on going issue the last three years it wasn’t as bad through the couple years but now I can’t go over 10 miles
And the coolant only goes in the reservoir and once it cools down it goes back into the radiator
 
Who makes the radiator? Is it the 160 thermostat or the stock 195 now? I’ve never had a coolant problem using mopar radiators so I’m leaning towards the 3 core radiator which have been known to cause problems. When you installed the radiator did you lay the fan clutch down or prop it upright. It gets fudged up if you lay them down. There is a check for the fan clutch, but I can’t remember it. I think it’s if you can spin the blade freely with engine off, but I’d confirm that. What mix of antifreeze are you using? Your in butt hot Florida so I can imagine this is frustrating, but stay at It. What pound pressure is your radiator cap? Is there fluid leaking from the coolant system somewhere? Water pumps can sometimes be difficult to seal properly and leaks can go undetected. What waterpump did you install? Our shit loves mopar and parts store brands can sometimes cause issues. That’s all I can think at the moment
 
I had overheating problems and discovered the radiator cap was bad. I replaced it with what I think was a Crown part. Still overheated. So I replaced it again with a Stant part. Still overheated. So I replaced it again with the Mopar OEM part. No more overheating problems.
 
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My '04 LJ runs a bit warm too. I replaced what I though was a leaky water pump, but it seems to seep still perhaps from bolts that go through water pump into water jacket. Autozone water pump had a different style impeller, one that looks like an alternator fan vs one I replaced that is closed and round like a conventional centrifugal pump. I think the conventional stye might be better. I bought a lower temp thermostat which I haven't yet installed. A couple of thoughts: The fan clutch should be fairly easy to turn when cold, and should be pretty well locked up if engine and radiator is hot. Try turning fan cold and hot by hand with engine off. Do you have a big blockage in front of grille? Bugs on A/C condenser? I have had some success over the years with Redline Water Wetter. It is an additive which increases heat transfer capability of coolant. Pure water is a better coolant than pure antifreeze, so don't run a higher concentration than you need for freeze protection. I would check for a bad head gasket. If when you were purging for 45 minutes, was it still blowing bubbles? If combustion gases are getting into the cooling system, overheating will follow. Sometimes head gasket leaks don't show up on a cool engine. I think there are test kits for the presence of combustion gases in the coolant. I've never used one, but have seen lots of bad head gaskets that could be diagnosed without a coolant test. Have you tried running premium? If your ECM is running a lot of spark advance, or if the engine is running lean, even on one cylinder, that could show up as overheating.
Hope this helps. Let me know what cures your Wrangler, as I may end up with the same problem.
 
Have you figured it out yet? I have the same problem. I can drive around town all day. After only a few minutes driving 60 down the highway the temp goes into the red. I turn the heater on and within 20 seconds it’s back to normal.
 
Have you figured it out yet? I have the same issue with my 04. I can drive around town all day with no problem. The minute I head out of town and 5 minutes at 60 mph the temp goes into the red. I turn on the heater and within 20 seconds it’s back to normal.
 
If there's an O'Reilly or Autozone nearby, they'll rent you a combustion leak detector tester. Id recommend doing that. A lower temp thermostat, although may help, is not the answer to the problem. If you don't know how to use the tester, ask at the store or YouTube it, its a very simple process.
 
I've been trying to pinpoint exactly what's causing my 04 TJ to overheat as well and I'd like to point out something I didn't realize was a thing. Some of you may already be aware, but the OE coolant temp gauge does not give an accurate coolant temp reading the same way the oil pressure gauge does not give accurate oil pressure readings.

I figured this out by accident when my Jeep threw a code and I plugged in my code reader to check it out. Basically, if the needle in the temp gauge is even slightly above 210, your actual temps could range anywhere from 215-250 with the needle still on the "0" in 210.

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In the pic, it's showing just above 210 what I expected to be 212-215, as a few others have reported, but I've seen temps on the scanner hit 250 with the needle in the exact same spot. Obviously that's no freaking bueno. The issue is exaggerated with the AC on and only delayed slightly with it off. Cranking the heater to max will eventually bring the temps down.

So far I've tried everything everyone else has: 2-core radiator - helped a bit but once temps hit 215 it was game over and it wouldn't cool down. I inspected the factory radiator, which looked good, and reinstalled it.

Flowcooler pump: mixed results but did not cure the problem. It's still installed, for now.

180 thermostat: before temps go over 215, temps will hold at 195-200 like they used to with the 195 tstat so no changes to report. It's still in there for now and will probably stay in there, I live in South Texas where there's no such thing as winter.

New radiator hoses: no changes but the old ones needed to go.

The fan clutch seems like it's good, it has what I believe is good resistance and doesn't spin a full turn by hand when the Jeep is cold, I haven't checked it hot. A new one is on the way along with a new radiator cap and overflow tank (the old one is pretty nasty).

I'm going to check the coolant level again after it cools down at work later today. I'm fairly confident I got all the air out when I reinstalled the factory radiator. I have a steep driveway and let it get to operating temp with a funnel full of coolant in the rad.

If the cap and clutch don't work, I'll replace the pump with a Mopar pump and get the radiator pressure tested, but honestly, it's starting to feel like there's no end in sight for this. I'm getting frustrated enough by it that I've kind of developed a case of "fk-it, give me a reason to V8/OM617 swap it", which sucks, because it's only got 83k on the clock.

I've been curious if my transmission isn't a part of the problem. It's got the 42RLE with a RubiCrawler and the tunnel gets H O T. So hot that if I keep my garage door opener in the pocket by the coin holder, after 20 minutes of driving the door opener is so hot it won't work. On the bright side, my coffee never gets cold. I picked up a Derale trans cooler but, unfortunately, it's not going to work with my suspension. How much heat from the trans cooler do you think is soaking the radiator?

Luckily it's only been in the mid-high 90's the past few weeks but I'm still sick of driving around with the heater on and coolant temps in the 220's-230's.

Any suggestions are appreciated.
 
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No, putting an electric fan on would be a horrible, stupid decision. That will likely just lead to more issues.

That 3-core "aluminum radiator" is probably part of the issue. Those things are known to be problematic, so I can't rule that out as part of the issue. You should be using a genuine OE Mopar radiator in all honesty.

Still, running at those temps isn't abnormal. What is the highest it gets up to?

Also, have you checked the radiator when the engine is cool to make sure it's full?
I disagree about the 3 core aluminum radiator, I have mine for over a year and have put 15K on it since with no issues at all. At the recommendation of my off road mechanic I went with a Ford Explorer fan clutch and plastic 10 blade fan conversion. I have dropped my temp to 195 normally and on hot days which the A/C on full blast it runs 210.
 
I disagree about the 3 core aluminum radiator, I have mine for over a year and have put 15K on it since with no issues at all. At the recommendation of my off road mechanic I went with a Ford Explorer fan clutch and plastic 10 blade fan conversion. I have dropped my temp to 195 normally and on hot days which the A/C on full blast it runs 210.
As long as it works for you!
 
I disagree about the 3 core aluminum radiator, I have mine for over a year and have put 15K on it since with no issues at all. At the recommendation of my off road mechanic I went with a Ford Explorer fan clutch and plastic 10 blade fan conversion. I have dropped my temp to 195 normally and on hot days which the A/C on full blast it runs 210.
It's a 3 row radiator, there is but one core. Yours may run fine with a 3 row radiator but the number of rows it has has no direct bearing on how well it will cool. In fact, Jeep went from a 2 row radiator to a 1 row radiator within a year or two of the introduction of the TJ. The new 1 row design had slightly better cooling characteristics. More rows does not mean better cooling.

P.S. The OE Mopar radiator has an all aluminum core.
 
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It's a 3 row radiator, there is but one core. Yours may run fine with a 3 row radiator but the number of rows it has has no direct bearing on how well it will cool. In fact, Jeep went from a 2 row radiator to a 1 row radiator within a year or two of the introduction of the TJ. The new 1 row design had slightly better cooling characteristics. More rows does not mean better cooling.

But Jerry... it's ALUMINUM! ;)
 
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