Coolant Overheating Issue

[Jwobes]

Hi Guys-

Has anyone experienced this? For reference-I live in Illinois, aka flat country. My coolant temp jumps over median at about 55+mph (highway speeds). Coolant levels are where they should be. But it is running extremely hot. Temp instantly decreases when I let off the gas pedal. Everything else seems to be running at normal temperatures.

I have a low-profile bumper and winch, so airflow is not restricted. I was wheeling this past weekend and was pushing it hard on rock crawling and it didn't go over median once. So, I'm confused on how and why this is happening at highway speeds when it is getting the most airflow.

Radiator has been power washed several times with the grille off to get any mud or dust in there. Its ticking me off that I can't figure this issue out and keep running hot. '

I need to figure this out before I head to windrock at the end of August so all ideas/advice please share.

Thank you.

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[ALeeL]

Thermostat not opening all the way, EGR cooler issue, or (and hopefully not) a blown head gasket. If you are maintaining coolant then it is likely the thermostat.

 

[Wrangler man]

Hi Guys-

Has anyone experienced this? For reference-I live in Illinois, aka flat country. My coolant temp jumps over median at about 55+mph (highway speeds). Coolant levels are where they should be. But it is running extremely hot. Temp instantly decreases when I let off the gas pedal. Everything else seems to be running at normal temperatures.

I have a low-profile bumper and winch, so airflow is not restricted. I was wheeling this past weekend and was pushing it hard on rock crawling and it didn't go over median once. So, I'm confused on how and why this is happening at highway speeds when it is getting the most airflow.

Radiator has been power washed several times with the grille off to get any mud or dust in there. Its ticking me off that I can't figure this issue out and keep running hot. '

I need to figure this out before I head to windrock at the end of August so all ideas/advice please share.

Thank you.

Those are some high temperatures but not completely off the chart. These Wrangler EcoDiesel configurations will shut down to limp mode protecting the engine from anything catastrophic. The cause is the engine bay is so small the engineers fit everything into this small engine bay. Example being the airbox found on the Ram is almost twice as large as these Wranglers due to the limited space. Don't forget they also had to raise the alternator for the water forging capability which is different than the Ram or the Cherokee that came with the Eco diesel. I live in one of the most hottest climates in the nation so I suffer from the same. The only time I've heard it causing a real problem is when you're towing. Too many people thought they could stack a rooftop tent pull a trailer and mash the pedal when climbing grades at extreme temperatures. You cannot treat a diesel that way if you do it will go into limp mode. A gas engine on the other hand doesn't have that protection and most times doesn't suffer from the extreme temperatures Wrangler owners are used to just mash in the pedal to the floor and running at a very high RPMs. These diesels do not like that. Even then as I mentioned it will go into limp mode to protect the engine. The fan may be extremely noisy but it's extremely effective that's why when you're wheeling you don't have the same temperatures. I would suggest turning your gear selector indicator on. Looking at your pictures you don't have this on and it helps to monitor your RPMs along with the gear when you're experiencing these extreme temperatures. These Eco diesels have a sweet spot where they like to run you need to know the RPMs along with the gear when operating a diesel correctly. Hope this helps. Water is the most effective for heat displacement I will run higher percentage of distilled water in my radiator during the summer than I would during the colder months of the winter this has helped a small amount

 

[ChuckQue]

Those are some high temperatures but not completely off the chart. These Wrangler EcoDiesel configurations will shut down to limp mode protecting the engine from anything catastrophic. The cause is the engine bay is so small the engineers fit everything into this small engine bay. Example being the airbox found on the Ram is almost twice as large as these Wranglers due to the limited space. Don't forget they also had to raise the alternator for the water forging capability which is different than the Ram or the Cherokee that came with the Eco diesel. I live in one of the most hottest climates in the nation so I suffer from the same. The only time I've heard it causing a real problem is when you're towing. Too many people thought they could stack a rooftop tent pull a trailer and mash the pedal when climbing grades at extreme temperatures. You cannot treat a diesel that way if you do it will go into limp mode. A gas engine on the other hand doesn't have that protection and most times doesn't suffer from the extreme temperatures Wrangler owners are used to just mash in the pedal to the floor and running at a very high RPMs. These diesels do not like that. Even then as I mentioned it will go into limp mode to protect the engine. The fan may be extremely noisy but it's extremely effective that's why when you're wheeling you don't have the same temperatures. I would suggest turning your gear selector indicator on. Looking at your pictures you don't have this on and it helps to monitor your RPMs along with the gear when you're experiencing these extreme temperatures. These Eco diesels have a sweet spot where they like to run you need to know the RPMs along with the gear when operating a diesel correctly. Hope this helps. Water is the most effective for heat displacement I will run higher percentage of distilled water in my radiator during the summer than I would during the colder months of the winter this has helped a small amount

While I agree with everything you said, that coolant temp is unusual. Even when my oil temps were hitting 240-245* pulling a trailer up a grade I didn’t see coolant temps that high. I agree that he may have a bad thermostat or EGR issue. It’s worth looking into.

 

[Jwobes]

Thermostat not opening all the way, EGR cooler issue, or (and hopefully not) a blown head gasket. If you are maintaining coolant then it is likely the thermostat.

I have written these down for potential issues- I have an appointment with the dealer on the 14th as she is still under warranty. Thanks for the info and Ill update it once I get it figured out

 

[Jwobes]

While I agree with everything you said, that coolant temp is unusual. Even when my oil temps were hitting 240-245* pulling a trailer up a grade I didn’t see coolant temps that high. I agree that he may have a bad thermostat or EGR issue. It’s worth looking into.

This what I keep hearing- I have written down these potential issues and we have a date with the dealer on the 14th. Thank you!

 

[Jwobes]

Those are some high temperatures but not completely off the chart. These Wrangler EcoDiesel configurations will shut down to limp mode protecting the engine from anything catastrophic. The cause is the engine bay is so small the engineers fit everything into this small engine bay. Example being the airbox found on the Ram is almost twice as large as these Wranglers due to the limited space. Don't forget they also had to raise the alternator for the water forging capability which is different than the Ram or the Cherokee that came with the Eco diesel. I live in one of the most hottest climates in the nation so I suffer from the same. The only time I've heard it causing a real problem is when you're towing. Too many people thought they could stack a rooftop tent pull a trailer and mash the pedal when climbing grades at extreme temperatures. You cannot treat a diesel that way if you do it will go into limp mode. A gas engine on the other hand doesn't have that protection and most times doesn't suffer from the extreme temperatures Wrangler owners are used to just mash in the pedal to the floor and running at a very high RPMs. These diesels do not like that. Even then as I mentioned it will go into limp mode to protect the engine. The fan may be extremely noisy but it's extremely effective that's why when you're wheeling you don't have the same temperatures. I would suggest turning your gear selector indicator on. Looking at your pictures you don't have this on and it helps to monitor your RPMs along with the gear when you're experiencing these extreme temperatures. These Eco diesels have a sweet spot where they like to run you need to know the RPMs along with the gear when operating a diesel correctly. Hope this helps. Water is the most effective for heat displacement I will run higher percentage of distilled water in my radiator during the summer than I would during the colder months of the winter this has helped a small amount

I know exactly what youre talking about as I have experienced "limp mode" once when I was unaware of the overheating coolant issue. Fan is working 100% as it sounds like a fighter jet about to take off so that is working the way it should. I think from everyone else's comments it seems like a thermostat or EGR issue. We have a date with the dealer on the 14th. I really appreciate your reply to help me figure out what the issue is, I will update the post when I figure this out. Thank you

 

[Wrangler man]

I know exactly what youre talking about as I have experienced "limp mode" once when I was unaware of the overheating coolant issue. Fan is working 100% as it sounds like a fighter jet about to take off so that is working the way it should. I think from everyone else's comments it seems like a thermostat or EGR issue. We have a date with the dealer on the 14th. I really appreciate your reply to help me figure out what the issue is, I will update the post when I figure this out. Thank you

I forgot to mention what many know but they let it fall by the wayside and never brought it to light asking why not in the US. What I'm talking about all previous to current diesel model Wranglers produced outside the United States automatically were fitted with the functional air scoop to relieve the extreme heat that builds up under the engine. Only the US models do not have this but no one is calling FCA out on this flaw that should be a must they knew it needed it that's why European Wranglers with diesels have it. And the fake vents on a Rubicon that are altered and opened to let hot air out or cool air in do not function correctly and it's been proven nor was it ever engineered to be such. The answer in the option that should be given to us Wrangler Diesel owners is an oem European style Hood. I feel strongly this would alleviate these high temperatures at highway speeds.

 

[oldcjguy]

Radiator has been power washed several times with the grille off to get any mud or dust in there. Its ticking me off that I can't figure this issue out and keep running hot.

You need to be careful with this. Never power wash a radiator. Just hose it down. Check and see if the fins in the radiator are bent over. Power washing can flatten them over and restrict air flow.

 

[Plongson]

The thermostat is pretty easy to access but you are going to loose coolant just checking it...on top of that, "burping" the air when refilling takes a while and patience

 

[Jwobes]

You need to be careful with this. Never power wash a radiator. Just hose it down. Check and see if the fins in the radiator are bent over. Power washing can flatten them over and restrict air flow.

I should have mentioned that it was on a low setting and none of the finds were bent

 

[Jwobes]

The thermostat is pretty easy to access but you are going to loose coolant just checking it...on top of that, "burping" the air when refilling takes a while and patience

To be honest, I have no idea what the thermostat even looks like, but losing coolant isnt an issue, I have jugs of it in the shop. What would I be checking for exactly?

 

[Jwobes]

I forgot to mention what many know but they let it fall by the wayside and never brought it to light asking why not in the US. What I'm talking about all previous to current diesel model Wranglers produced outside the United States automatically were fitted with the functional air scoop to relieve the extreme heat that builds up under the engine. Only the US models do not have this but no one is calling FCA out on this flaw that should be a must they knew it needed it that's why European Wranglers with diesels have it. And the fake vents on a Rubicon that are altered and opened to let hot air out or cool air in do not function correctly and it's been proven nor was it ever engineered to be such. The answer in the option that should be given to us Wrangler Diesel owners is an oem European style Hood. I feel strongly this would alleviate these high temperatures at highway speeds.

Yeah- I have a sport model so I do not have any function air vents in the hood

 

[Wrangler man]

Yeah- I have a sport model so I do not have any function air vents in the hood

Rubicon simulated vents are only that. Even when opened up they do not aid in any cooling at all. Have the Sport model too. Always looking for that European OEM functioning vented hood for the Wrangler. No luck so far.

 

[Kleiss1]

Your oil is 255 on flat ground?

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