Improving the cooling on our TJs

When my rig was stock, if I would idle for a while in 100F+ with AC on, then it would start running rough, and once or couple of times I got misfires. The heat soak in some extreme cases can cause misfire even on running rig.

I’m definitely aware of the heat soak issue bc it only happens when the rig is idling after driving around. That’s why the louver is installed and the fuel lines, rail, uppipe, and downpipe are wrapped. It helped but didn’t eliminate the issue. Not sure if the spark plugs are going to help but I did it anyways. I’ll install the coil rail after I splice in a new plug tomorrow (storming outside).
 
I’m definitely aware of the heat soak issue bc it only happens when the rig is idling after driving around. That’s why the louver is installed and the fuel lines, rail, uppipe, and downpipe are wrapped. It helped but didn’t eliminate the issue. Not sure if the spark plugs are going to help but I did it anyways. I’ll install the coil rail after I splice in a new plug tomorrow (storming outside).

The fan on the louver that I have installed is actually lowering the IAT temperature. It pulls cold air through the louver and blows it on the injectors 3 and 4.
Do you see any misfires or rough idle before Intake Manifold reaches like 200F+? Which cylinders are getting misfires?
 
Yes I always drain the block. My cooling system was absolutely jacked when I bought the rig. It worked great when I left for training in NY, but apparently it degraded while I was away even though it was 50/50 G05.

I was not happy when I pulled my radiator cap after seeing the temps just a bit too high in idle. Pulled more chunks out today with a magnet.

Did you even consider coolant inline filter? Is it possible that your heater core is falling apart and sending chunks into the cooling lines?

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Did you even consider coolant inline filter? Is it possible that your heater core is falling apart and sending chunks into the cooling lines?

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I considered it until I read about the filter leaking for people. Also, I thought I was good and had to leave for phx an hour after I finshed the last flush. I’m just now back to town to work on this again so I’m re-evaluating things.

I don’t think it’s my heater core is the issue. I back flushed it twice recently and things looked pretty good both times. And these chunks were in my block the first time I ever drained it so I know my block/head were compromised. I just thought all was good bc I had been good to go for two years.

Imo it’s my block/head. My system was so bad when I purchased the rig that I had to have my freeze plugs replaced bc one failed when the first ever thermocure ate the corrosion.
 
I considered it until I read about the filter leaking for people. Also, I thought I was good and had to leave for phx an hour after I finshed the last flush. I’m just now back to town to work on this again so I’m re-evaluating things.

I don’t think it’s my heater core is the issue. I back flushed it twice recently and things looked pretty good both times. And these chunks were in my block the first time I ever drained it so I know my block/head were compromised. I just thought all was good bc I had been good to go for two years.

Imo it’s my block/head. My system was so bad when I purchased the rig that I had to have my freeze plugs replaced bc one failed when the first ever thermocure ate the corrosion.

If you got the corrosion to the level that you have freeze plug failing, then it means that you have a big corrosion problem, and you might want to have the filter protecting the radiator. It would catch all the junk going into the radiator
 
The fan on the louver that I have installed is actually lowering the IAT temperature. It pulls cold air through the louver and blows it on the injectors 3 and 4.

I’m glad it’s working for you that’s great to hear. I’ll have an intercooler in that location if all goes well.

Do you see any misfires or rough idle before Intake Manifold reaches like 200F+? Which cylinders are getting misfires?

I need to drop my IATs for when I’m under boost not so much for idle although lower temps would be nice all the time. My engine bay is crazy hot from the manifolds imo.

My IATs are usually under 200* when in idle but not always. I get a rough idle sitting lower at like 170* if I’ve been driving the rig. I don’t really get misfired if I just idle without driving the rig.

99% of the time i pop a code for cylinder #3 but I recently popped one for #4 that’s why I didn’t a compression test when pulling the spark plugs.

My gauge tracks the real time misfires and I watch them sometimes in idle. There’s way more misfires happening than I would have realized. I believe the PCM pops the CEL of they happen enough in a specific time frame. I didn’t pop a code when I took the following photos, yet you can see misfires are happening. (Not sure why the guage only tracks 1-4 but I’ll ask the company soon).

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If you got the corrosion to the level that you have freeze plug failing, then it means that you have a big corrosion problem, and you might want to have the filter protecting the radiator. It would catch all the junk going into the radiator

It was like that when I bought the rig. That was almost three years ago. It overheated over 260* during the initial emissions test bc the electric fan was failing and he had a 210* thermostat installed.

After the freeze plugs were changed flushed and then installed all mopar components. Then went on to rock crawl during two Tucson summers in man 110* plus days in 4low without any issues.

With that said I know I have an issue to handle now that the two rounds of thermocure didn’t handle it (it got me to phx so I thought maybe I’d be good).

I appreciate you mentioning the filter. It’s different than the style I was looking at.
 
Cylinders 3 and 4 are the most impacted by the heat soak. The question is if you add inter cooler right on top of them, aren’t you going to overheat them even more?
 
Cylinders 3 and 4 are the most impacted by the heat soak. The question is if you add inter cooler right on top of them, aren’t you going to overheat them even more?

Yea they get blasted from the manifolds. I pop #3 almost exclusively but on a rare occasion I’ll pop a #1 or #4.

Imo I still have a heat soak issue, and I’ll be doing the manifolds to see if that helps it. I would have installed them during my spring visit but the headers were damaged.

I decided to change the spark plugs just to make sure that’s not a contributing issie. They had lived through a false lean condition which was blasting fuel on them (fixed the o2 wiring during my visit) so I changed them out earlier today to eliminate them from possibly causing problems.

The Banks intercooler goes on top and is water cooled from a heat exchanger in the grill. However, it’s gonna be an experiment bc I’ll be re-purposing the Setrab transmission cooler to be my heat exchanger since there’s not enough room in the grill for the banks heat exchanger.

I don’t expect the intercooler location to cause any heat soak issues bc it will be in the back center so it won’t cover up the vents much. And it will be liquid cooled with the fan pulling through the grill and water pump circulating the fluid. TBH I’ve never heard or read about an intercooler heat-soak issue being discussed.

Overall, I’ll be thrilled if the intercooler drops temps by even 20*. I spend most of my time in light boost. I use water/meth injection for cooling IATs at full throttle.
 
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Sorry to interrupt, but does anyone have a link to a Mopar radiator for a 2004 tj? I can't find one for sale.

I did not find one for automatic. I bought the one for 2005, which will bolt in, with minor change into transmission cooler lines.
If you have manual, you can just buy the one for auto, and just seal the transmission cooler.
 
No need to seal the transmission cooler, it's not connected at all to the main radiator... it's completely separate. Only seal it if you want to keep bugs out lol.

I thought about long term corrosion from the inside. Oil usually prevents corrosion, but if it is exposed to elements in the air, like humidity etc, this will be a problem
 
I thought about long term corrosion from the inside. Oil usually prevents corrosion, but if it is exposed to elements in the air, like humidity etc, this will be a problem

if it were me, I might cap one end, fill it with oil, let it drain back out, and then cap the other end, though my concern would be less for corroding through and more that I just never know when I might want a heat exchanger to cool something like engine oil, or power steering.

Bonus if it's capped in winter when the air is as dry as possible.
 
I just finished reading this entire thread so I hope no one yells at me. ;-) I have a 2005 LJ that I am not having cooling issues with, but I also have a 2003 TJ block and head in my 1987 MJ. Can anyone tell me the first year the 4.0 block had a drain plug because the one in my MJ does not? Yes I’m sure it’s a 2003 block based on the block stamp.
 
I just finished reading this entire thread so I hope no one yells at me. ;-) I have a 2005 LJ that I am not having cooling issues with, but I also have a 2003 TJ block and head in my 1987 MJ. Can anyone tell me the first year the 4.0 block had a drain plug because the one in my MJ does not? Yes I’m sure it’s a 2003 block based on the block stamp.

Fwiw, I had a ‘99 for a brief period of time that had a drain plug.
 
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