Overheating issue

Mora

Mora

TJ Enthusiast
Joined
Jun 17, 2020
Messages
128
Location
Ventura County, California
2005 Automatic Jeep SE 65k miles
I made a post about this about 2 weeks ago but I want to somewhat follow up on recent events. I first noticed when my engine temp gauge was going past the 210 mark (totally normal is what everyone said). I made a post and it was nothing to worry about. Ended up getting an OBDII Scanner for future events and to see actual engine temps and the temps ran to about 215/216. No biggie. Today, I plugged in my scanner and it read 225 (had AC full blast). Don't know how normal this is. If it is normal than I have nothing to worry about! I checked coolant levels last week and they seemed fine. Going to check them again once it cools down.

I do have 35's with 4.88 gearing. Could that be the reason as to why its running hotter? And is it a bad thing that it was running at 225? Mainly fluctuated between 221-225. This was purely while driving. While at a stoplight, it fluctuated between 217-220.

I took my Jeep to my mechanic for other reasons and while he was at it, had him read the transmission temps (don't know how accurate those are though scanners) and it read right around 200. I had already ordered an aux transmission cooler a few days ago and it should get here soon, so those temps will go down. The PO did do a tummy tuck but I don't know if that is related to engine and transmission temps being higher.

Has anyone experienced this before and is this something that I need to even be worried about? Can't thank you all enough for the help you've been over the last few months.
 
It does seem a little warmer than usual, but not enough to be concerned about. For context, my 4.0 with a new Mopar radiator, Hayden HD fan clutch, Stant 195 stat, and original mopar water pump runs about 200-210 at all times. The biggest change was adding the fan clutch, strangely, which even keeps the Jeep cooler while at speed.
 
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Those temps are a bit high but nothing to be alarmed over yet. Do you know what kind of a radiator is installed? Aftermarket radiators tend to cause the engine to run hotter than it would with the correct Mopar radiator installed.
 
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Fan clutch is one thing to check as mentioned above. Especially if it heats up more at idle but cools back down some when you are driving faster. That could also mean you are low on coolant and have a small leak somewhere.

If you smell the coolant and hear a gurgling boiling sound after it's gotten hot, look and see if you are boiling coolant in your overflow. That means you've lost pressure on your coolant system. Easiest thing to check for that is buying a new radiator cap. Not sure if any of these will apply to you, but they were all things I ran into. on my 2005 Auto LJR
 
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How does the coolant look? Are all cooling system parts original?

If the coolant is dirty it can be impacting your cooling system's efficiency, as will underperforming worn out parts like a worn fan clutch, lazy thermostat, plugged radiator, or water pump.

While 35's and 4.88 gears can put a load on the engine, 225* is still on the high end of things. My cooling system is mostly new, but I can tow a loaded trailer on a 100* day through the hills and not pass 210*.
 
Jerry Bransford said:
Do you know what kind of a radiator is installed?
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I still believe it's the OEM radiator. I would have to check and then contact the PO to be 100% certain.

jeepguy03 said:
How does the coolant look? Are all cooling system parts original?

While 35's and 4.88 gears can put a load on the engine, 225* is still on the high end of things. My cooling system is mostly new, but I can tow a loaded trailer on a 100* day through the hills and not pass 210*.
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By my knowledge, all cooling system part are original. I checked the coolant and all seems to be fine. It visually looks good and the levels are good too.
 
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TJ4Jim said:
Is the electric fan cycling off and on with temps
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When starting my car yesterday, I noticed that my radiator fan was always on (don't know if that is what you are referring to). I kept an eye as my car warmed up to operating temperatire and it still stayed on.

AdventureWill said:
Fan clutch is one thing to check as mentioned above. Especially if it heats up more at idle but cools back down some when you are driving faster. That could also mean you are low on coolant and have a small leak somewhere.

If you smell the coolant and hear a gurgling boiling sound after it's gotten hot, look and see if you are boiling coolant in your overflow. That means you've lost pressure on your coolant system. Easiest thing to check for that is buying a new radiator cap. Not sure if any of these will apply to you, but they were all things I ran into. on my 2005 Auto LJR
Click to expand...

If anything, it cools down more at idle and gets hotter when driving. When I was driving I noticed that it got up to 225 but when I slowed back down it went to about 219.
 
Forget the mileage for a moment and pay attention to the age. I am telling you what I would do if it were mine. I would replace the fan clutch, T-stat, and radiator cap, and flush the system with Thermocure for starters (The flush may do the trick). New coolant after thorough flushing. If that did not solve my problem, I'd be looking at radiator and water pump as well. All of those parts are cheap and the job is easy. Did I mention hoses? If the lineage of these parts is unknown, don't be afraid to go scorched earth. Rarely does anyone regret replacing a 15 year old cooling system. Some penny pinchers might disagree. If you want to pinch pennies, get a Toyota Corolla and change the oil once a year with whatever is on sale.
 
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Mora said:
When starting my car yesterday, I noticed that my radiator fan was always on (don't know if that is what you are referring to). I kept an eye as my car warmed up to operating temperatire and it still stayed on.



If anything, it cools down more at idle and gets hotter when driving. When I was driving I noticed that it got up to 225 but when I slowed back down it went to about 219.
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Is the fan shroud installed and intact ?
 
Flivver250 said:
Forget the mileage for a moment and pay attention to the age. I am telling you what I would do if it were mine. I would replace the fan clutch, T-stat, and radiator cap, and flush the system with Thermocure for starters (The flush may do the trick). New coolant after thorough flushing. If that did not solve my problem, I'd be looking at radiator and water pump as well. All of those parts are cheap and the job is easy. Did I mention hoses? If the lineage of these parts is unknown, don't be afraid to go scorched earth. Rarely does anyone regret replacing a 15 year old cooling system. Some penny pinchers might disagree. If you want to pinch pennies, get a Toyota Corolla and change the oil once a year with whatever is on sale.
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Electric fan on the late model SE's.
 
Flivver250 said:
Forget the mileage for a moment and pay attention to the age. I am telling you what I would do if it were mine. I would replace the fan clutch, T-stat, and radiator cap, and flush the system with Thermocure for starters (The flush may do the trick). New coolant after thorough flushing. If that did not solve my problem, I'd be looking at radiator and water pump as well. All of those parts are cheap and the job is easy. Did I mention hoses? If the lineage of these parts is unknown, don't be afraid to go scorched earth. Rarely does anyone regret replacing a 15 year old cooling system. Some penny pinchers might disagree. If you want to pinch pennies, get a Toyota Corolla and change the oil once a year with whatever is on sale.
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I am for sure overdue for a replacement of my cooling system. Will have to add this to this list. I will start off with Thermocure and see if that resolves any issues. If not, I will move onto the other items.
 
Since your in a warm weather area I would probably dump the coolant and run distilled water for several days, dump and repeat just to get things cleaned out. Otherwise as Flivver suggested with the pump and "T" stat.
 
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Does it run 225 on the highway or just around town? Curious on the answer. Unfortunately I also have 35's with 4.88 and a 42rle and it will run 220-225ish on the highway with AC on hot day. Even after I rebuilt the cooling system with OEM parts it still runs that temp on the highway but cooler around town around 210 w/o AC, 210-215 w/ AC. I also later add a trans cooler in front of the rad suspecting the load from the 35's and bad overdrive gearing. It helps tranny temps but no change in ECT.

IMO 225 while hotter is still no big deal. Its still a long way from overheating or damage. The key question is if its a change or getting worse.
 
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Juggernaut said:
Does it run 225 on the highway or just around town? Curious on the answer. Unfortunately I also have 35's with 4.88 and a 42rle and it will run 220-225ish on the highway with AC on hot day. Even after I rebuilt the cooling system with OEM parts it still runs that temp on the highway but cooler around town around 210 w/o AC, 210-215 w/ AC. I also later add a trans cooler in front of the rad suspecting the load from the 35's and bad overdrive gearing. It helps tranny temps but no change in ECT.

IMO 225 while hotter is still no big deal. Its still a long way from overheating or damage. The key question is if its a change or getting worse.
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When I experienced it being 225 it was around town with AC full blast . Usually on the highway it gets around 217 if the AC is on. Always runs cooler without AC. When I bought the Jeep, temps seemed to be fine. Only until this last 2 weeks I’ve noticed them rising. And yesterday was the highest I’ve seen it. I’ll have to keep an eye out to see if it goes any higher. Also have to take into consideration that the heatwaves have been pretty bad out here where I live. Some of the highest in a long long time.
 
Your actual temperature is probably on par with many in hotter areas. That said, no reason not to have a fresh cooling system operating at it's peak. I am in the hot middle east and mine has a fresh stock cooling system. I never exceed 210° if the gauge is semi-accurate. The Thermocure, new Mopar radiator (had a Chinese knock-off) and the Hayden fan clutch were probably the biggest improvements. Also, never under-estimate the value of good quality anti-freeze.
 
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Mora said:
When I experienced it being 225 it was around town with AC full blast . Usually on the highway it gets around 217 if the AC is on. Always runs cooler without AC. When I bought the Jeep, temps seemed to be fine. Only until this last 2 weeks I’ve noticed them rising. And yesterday was the highest I’ve seen it. I’ll have to keep an eye out to see if it goes any higher. Also have to take into consideration that the heatwaves have been pretty bad out here where I live. Some of the highest in a long long time.
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The OE cooling system has zero problems in such conditions which are mild compared to what we see here in the deserts of the southwest.

Mopar radiator & pump with a good quality fan clutch is the cure.
 
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