Coolant temp overheat

[AVGeek99]

I've a 2021 JLU w/the 2.0T. The coolant temperature trend exceeds 200°F only infrequently, no matter the time of year and then only if I'm climbing a grade or towing the loaded motorcycle trailer in the heat of summer. It may increase a bit if I really press my right foot down, too, but that's understood. Lifting my foot then causes the number to go back down as expected.

If I saw the bolded numbers during daily, steady-state driving, that'd be cause for immediate concern, if only because after 5 years of ownership they'd be outliers.

Possibly the owner's driving habits, and/or frequency of elevation changes during everyday driving, has an effect here.

I tend to pay attention to the coolant temp more when the engine is working harder (climbing a grade), or not at all (idling at a light). Climbing a grade causes the temp to go up for obvious reason, idling at a light becuase the engine is running slow and not circulating coolant as quickly.

I need to get in the habit of checking more under normal "steady state" driving as you say. I've I'm just going down a levelish road at 40+mph the temps to fall into the low 200s, occasionally upper 190s. Saturday just surprised me that it was just constantly heating up to about 225 and then the fan was kick in and cool it to the 190s, but as soon as the fan just off it would climb right back to 225. This went on all day.

Maybe it's just "working as designed"; if I wasn't climbing a grade at a slow 20-30mph, I was going 8-12mph or slower in 4-low. If it was in the 90s or warmer, I wouldn't really think anything of it, but it was the mid 50s.

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[jimim]

I've a 2021 JLU w/the 2.0T. The coolant temperature trend exceeds 200°F only infrequently, no matter the time of year and then only if I'm climbing a grade or towing the loaded motorcycle trailer in the heat of summer. It may increase a bit if I really press my right foot down, too, but that's understood. Lifting my foot then causes the number to go back down as expected.

If I saw the bolded numbers during daily, steady-state driving, that'd be cause for immediate concern, if only because after 5 years of ownership they'd be outliers.

Possibly the owner's driving habits, and/or frequency of elevation changes during everyday driving, has an effect here.

NOW that I AM FILLED PROPERLY i hover at 188-198. i go over 200 like said above pretty much. I hit 212 the other say accelerating uphill passing someone going like 15 mph. let my foot off gas still going uphill and it settled back in. but over all since i filed i don't go over 200 on a regular basis like i was.

all i got ot say is my tank has been low for LIKE EVER now when i think about my temps. i was ALWAYS IN THE 200-220 RANGE. this is the coolest i have run in i don't know how long. we are in cold weather now so hopefully when its spring and warms up and i start tow the boat again nothing pops up.

 

[jimim]

yo guys I was a rebel this morning and DIDN'T take a coolant pic. . . actually it was cause I was running late getting my daughter to school. lol
i know you ALL were wondering what was going on since i have been obsessing. . .

i will say i might just bag this ol' combustion nonsense and grab me one of those new electric jeeps that came out today. . . .lol

noooooo way you will have to pry a wrangler steering wheel out of my dead cold hands. . . i might drive other stuff but i will never even not own a wrangler. everyday behind the wheel i am happy. i have owned alot of other trucks that i have liked but at some point i always get bored of them and want something else. . . not my wrangler. it's only my second but i loved both.

 

[jimim]

Ok measured this morning. I was a bit down for first time. I didn’t measure yesterday cause I was late. Tuesday morning I was good so I lost a bit Wednesday or Tuesday during the day driving.

I added 2 oz. Came back up to where it was. Added 2 more to be a bit higher but still in range.

Nothing on floor in garage.

So question. Should I call them to see what they say?

TOP DOWN PICS
Tuesday fine
Today lower
After additional 4 oz measured.

 

[jimim]

Stupid update for those who maybe find this down the road. . .

7 days with no drop. So we are looking at 2 weeks and like 1000k miles. at 500 miles after 7 days I had to throw in 2 ox cause of a drop. 7 days later no drop in 7 days.

So I'm fine. Listen I got 27k miles left on my extended warrenty. if shit goes sideways before that I ghost it. . . if we have a little drop here and there I drive it till it blows up and I trade it in for scrap. I hate car payments and this jeep has been good to me.

Now if this time next year they are trying to dump willy v8's. . . this jeep is dead to me. lol

 

[DrBob]

OP glad things are looking pretty good for you. I’m currently chasing down the exact issue you’re describing. We think we’ve narrowed it down to a leak in the EGR cooler. It’ll be replaced in the next couple of weeks and I’ll update. Very frustrating.

 

[jimim]

OP glad things are looking pretty good for you. I’m currently chasing down the exact issue you’re describing. We think we’ve narrowed it down to a leak in the EGR cooler. It’ll be replaced in the next couple of weeks and I’ll update. Very frustrating.

so what symptoms do you have cause I literally had and still have none minus the overheating in idle which was only cause it was bone dry but since it has been filled zero symptoms and my levels are now tight for past 10 days I think. I'm still checking daily when I remember.

How did you know and how did they figure it was the EGR cooler?

 

[DrBob]

so what symptoms do you have cause I literally had and still have none minus the overheating in idle which was only cause it was bone dry but since it has been filled zero symptoms and my levels are now tight for past 10 days I think. I'm still checking daily when I remember.

How did you know and how did they figure it was the EGR cooler?

First episode happened at idle. While outside the Jeep disconnecting my sway bar links, the fan kicked on and climbed to a speed I've never heard before. Quick glance at the instrument panel and the engine temp had shot up almost 250°. I shut it off, waited five minutes, the temp was back to "normal." Then drove normally off-road at between 10-20 mph for 17 miles without issue, stopped at our destination, and temp started shooting up again. I wasn't able to check the coolant level until the next morning, and the reservoir was empty. I topped it off, but within a day symptoms repeated, and again had to add more coolant.
I performed the usual visual inspection for leaks and couldn't find any. Mechanic crawled under, into, around the engine, including tracing all the coolant lines, and there were no tell-tale signs of any leaks. We placed a camera into all four cylinders, and there were no signs of a head gasket leak. Pressure test on coolant system failed. Slight positive on checking for products of combustion in the coolant.
The EGR cooler is the diagnosis essentially by process of elimination. Spoke with my mechanic today, and after his research, another point of failure could be in the head itself- the EGR cooling lines travel through the head- but this is less likely.
Definitely not as simple as finding leaks on my TJ!! Hopefully a new EGR cooler will be the answer- I will definitely update once installed.

 

[jimim]

My pressure test for a leak was negative but they won’t go any further till I drove it 500 miles and then they were going to take it further. I said 509 miles for me is like 3 days with my daughter’s tennis schedule. I’m at like 1200 miles and I added 2 oz like I said 10 days ago now. So I’m going to just keep driving till I have another issue and then they said they will take it further whatever the frig that means bit I’m good with it for now.

 

[jimim]

Hey guys. So here is updated pic. There is deff a decrease right? I called the shop and they said it’s still normal and no further testing is required. I don’t get this. It’s going down?

I called another dealership and they said bring it in but I also just don’t want to bring it in and they just do the same 1 leak test without dye.

Is it me?

This morning

November 23rd

 

[mwilk012]

Hey guys. So here is updated pic. There is deff a decrease right? I called the shop and they said it’s still normal and no further testing is required. I don’t get this. It’s going down?

I called another dealership and they said bring it in but I also just don’t want to bring it in and they just do the same 1 leak test without dye.

Is it me?

This morning

November 23rd

I’m going to come lock your hood closed for a month.

 

[jimim]

I’m going to come lock your hood closed for a month.

Ok so I’m fine then.

I know I have issues. I try I really do. Do you think I want to be like this. lol. I hear it from my wife and kids everyday.

Ok I’ll check like once a week from now on. 1 month is a bit extreme for me. lol

 

[Bob Burd]

Ok I’ll check like once a week from now on. 1 month is a bit extreme for me. lol

But probably what you need. This is pretty obsessive.

 

[ScotM]

I’m going to come lock your hood closed for a month.

That looks fine

But probably what you need. This is pretty obsessive.

 

[jimim]

Ok I know I was told to lock the hood and move on but it’s loosing coolant and technically it lost a lot which started all this so I took it to another dealer shop today. They said they were going to actually pull spark plugs. Camera s exactly could along with dye test and leak tests.

They found the leak in 1 hour. It was at the area of the stat I was told. Pics attached. They said I am good now. Turned into for claim. 100 bucks out.

So I said how come other place did leak pressure tests for 2 days and said nothing. Do drive it and see and how come you all found it instantly. He said guy working on your jeep prob had no experience. I said I was told he was there for 25 plus years and have seen it all. Bla bla bla. Who is right who is wrong. I don’t know bot they said it’s fixed. He said this is a very very well known weak point.

Ok I leave it to the pro’s now discuss.

I don’t know anything but all I know is why the hell did shop 1 do 1 test. Stopped fave up pretty much and told me to drive it and see what happens and shop 2 pretty much came in called me right back and mic dropped? Seriously.

Again I came here for help from all you guys cause I’m clueless but in those pics I see pink coolant marks. How can anyone with 2 working eyes who work on jeeps for a living not even see this?

Not judging. Just completely confused.

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