Nonstop overheating

[JeepxMopar]

Hello,
01 tj that I’ve been daily driving for years has decided to develop a minor overheating issue that I cannot chase down. I have replaced two radiators , thermo, water pump , clutch fan, and ensured all air is out of system. The problem is at idle like a light or drive thru , I will rise from 210 to about 215. This is when the thermostat kicks in and it goes back down. It isn’t continuing to fully overheat with this thermostat I think because it’s a mopar replacement but it can only last so long on this issue.
Now I know head gaskets can cause coolant system issues but I have no symptoms of head gaskets blowing or being bad. Haven’t done a compression test yet. That is my next step. Figured I’d reach out and see if anyone else has a slight overheating issue that they can not pinpoint. Thanks

 

[TheBoogieman]

215 isn't overheating. First thing I do is clean the system with something like Thermocure.

 

[cpwolf]

I would agree, 215 isn’t over heating.

You described the system heating up closed, and when the thermostat opens it cools down.

Now, I would think the thermostats at 195, so they should be open.

I also agree that you might want to run a cycle of Thermocure just to make sure it doesn’t have any fouling (rust) in there.

 

[ChasUGC]

Take a picture of your coolant and the overflow bottle. My guess is that your heater core needs a good flushing, but the pictures would tell a lot. If your coolant is orange with rust or full of crude in the bottom of the overflow, that would tell a lot too. In high summer temperatures with the AC on, and stuck in heavy traffic, my temperatures will rise, but I just open my windows, and turn off the AC until we start going good again. Then, my temperature goes down and I can turn on the AC. In 110F in the valley, on surface streets, I don't even bother to turn on my AC. And, my engine temps stay normal. I didn't have that problem when my Jeep was new, but after 20 years, she needs a little break from all the heat.

 

[macleanflood]

And do a combustion gas test if you suspect the head gasket...but I don't think you're there yet...

-Mac

 

[jjvw]

When it overheats, what is the temp?

 

[bohuggabee]

Hello,
01 tj that I’ve been daily driving for years has decided to develop a minor overheating issue that I cannot chase down. I have replaced two radiators , thermo, water pump , clutch fan, and ensured all air is out of system. The problem is at idle like a light or drive thru , I will rise from 210 to about 215. This is when the thermostat kicks in and it goes back down. It isn’t continuing to fully overheat with this thermostat I think because it’s a mopar replacement but it can only last so long on this issue.
Now I know head gaskets can cause coolant system issues but I have no symptoms of head gaskets blowing or being bad. Haven’t done a compression test yet. That is my next step. Figured I’d reach out and see if anyone else has a slight overheating issue that they can not pinpoint. Thanks

Heat soaking is an issue with all the large block tj’s... my jeep develops back pressure that soaks into the injectors and this flash steams the fuel mixture. One time i used aluminum foil and insulated my intake system. It worked amazing till the engine got warm. That wasnt my issue... if i sit at lights, though my gauge is fine, it still soaks heat and will lose idle. I even considered and entire redesign of a heat sinks to induct air like a lewis machine gun lol. I still want to do it. And one day i will. But until then. You make due.

To me. Aside from others are saying, check the seals or fuel pressure. Its an odd issue but if the fuel pump isnt regulating properly. It means that the engine is over heating from an idle imbalance of combustion. The injectors then over heat. If its burning more fuel than usual. Thats where its statting from

So check the injector seals and see. Often they have a residue or clue outside of them. Which means the fuel flow isnt cooling the injector enough. Is thats not cool then it builds slowly over time. Could be a simple o ring on an injector. Like i said thats rare but no one knows to look for it lol and itll look like a vacuum issue.

 

[jjvw]

Heat soaking is an issue with all the large block tj’s... my jeep develops back pressure that soaks into the injectors and this flash steams the fuel mixture. One time i used aluminum foil and insulated my intake system. It worked amazing till the engine got warm. That wasnt my issue... if i sit at lights, though my gauge is fine, it still soaks heat and will lose idle. I even considered and entire redesign of a heat sinks to induct air like a lewis machine gun lol. I still want to do it. And one day i will. But until then. You make due.

To me. Aside from others are saying, check the seals or fuel pressure. Its an odd issue but if the fuel pump isnt regulating properly. It means that the engine is over heating from an idle imbalance of combustion. The injectors then over heat. If its burning more fuel than usual. Thats where its statting from

So check the injector seals and see. Often they have a residue or clue outside of them. Which means the fuel flow isnt cooling the injector enough. Is thats not cool then it builds slowly over time. Could be a simple o ring on an injector. Like i said thats rare but no one knows to look for it lol and itll look like a vacuum issue.

All we ever learned a year ago is that his engine gets up to 215F, which is not overheating.

 

[Link]

Hello,
01 tj that I’ve been daily driving for years has decided to develop a minor overheating issue that I cannot chase down. I have replaced two radiators , thermo, water pump , clutch fan, and ensured all air is out of system. The problem is at idle like a light or drive thru , I will rise from 210 to about 215. This is when the thermostat kicks in and it goes back down. It isn’t continuing to fully overheat with this thermostat I think because it’s a mopar replacement but it can only last so long on this issue.
Now I know head gaskets can cause coolant system issues but I have no symptoms of head gaskets blowing or being bad. Haven’t done a compression test yet. That is my next step. Figured I’d reach out and see if anyone else has a slight overheating issue that they can not pinpoint. Thanks

As mentioned, that’s not overheating. Mine fluctuates a little as well. It’s normal.

 

[Link]

Heat soaking is an issue with all the large block tj’s... my jeep develops back pressure that soaks into the injectors and this flash steams the fuel mixture. One time i used aluminum foil and insulated my intake system. It worked amazing till the engine got warm. That wasnt my issue... if i sit at lights, though my gauge is fine, it still soaks heat and will lose idle. I even considered and entire redesign of a heat sinks to induct air like a lewis machine gun lol. I still want to do it. And one day i will. But until then. You make due.

To me. Aside from others are saying, check the seals or fuel pressure. Its an odd issue but if the fuel pump isnt regulating properly. It means that the engine is over heating from an idle imbalance of combustion. The injectors then over heat. If its burning more fuel than usual. Thats where its statting from

So check the injector seals and see. Often they have a residue or clue outside of them. Which means the fuel flow isnt cooling the injector enough. Is thats not cool then it builds slowly over time. Could be a simple o ring on an injector. Like i said thats rare but no one knows to look for it lol and itll look like a vacuum issue.

Shhhh…..adults are talking.

 

[jjvw]

Shhhh…..adults are talking.

The OP disappeared almost a year ago.

 

[Link]

The OP disappeared almost a year ago.

What’s your point? The conversation has restarted.

 

[HammeredSole]

I had an aftermarket radiator cap that wasn't sealing and allowing the system to pressurize, and it caused the temp to creep up past 210. I replaced it with a Mopar item and it fixed that. Maybe worth checking out.

 

[Link]

I had an aftermarket radiator cap that wasn't sealing and allowing the system to pressurize, and it caused the temp to creep up past 210. I replaced it with a Mopar item and it fixed that. Maybe worth checking out.

My Jeep didn’t have any pressure in the radiator when running when I bought it. Replaced the cap with a new one (went Mopar for it). A few days later the top radiator tank split. Cap hadn’t been sealing, probably for a long time, and the radiator was on its last legs. Once the radiator pressurized like it should, it split. Now have a new Denso radiator on it and it’s pressurized and keeping everything at the right temp.

Friend called me one day last winter. He was a few hrs from home and had a split in the top tank of his Toyota Camry radiator. I told him to take the radiator cap off and cut the seal on the cap to prevent pressure from building up. Then, top off the coolant and drive home. It was cold outside so not a lot of cooling capacity needed. Told him it’ll destroy your radiator cap but those are cheap and you’ll get home with no issues as the radiator won’t be pressurizing and forcing coolant out the top. Sure enough, zero issues getting home. Might have been an issue in the summer but not in the winter.

 

[ChasUGC]

All we ever learned a year ago is that his engine gets up to 215F, which is not overheating.

Exactly. That's about what my Jeep has been running at for the last 27 years on the same engine(210-215). Overheating as shown on the gauge is about (240-260). 210-215 is completely normal operating temperature as designed. Trying to force the engine to operate cooler will cause more wear and tear.

 

[Larry L TJ]

Exactly. That's about what my Jeep has been running at for the last 27 years on the same engine(210-215). Overheating as shown on the gauge is about (240-260). 210-215 is completely normal operating temperature as designed. Trying to force the engine to operate cooler will cause more wear and tear.

Good information for a new TJ owner. I noticed my 04 usually runs about 208/210 unless Ac is on or going up a long hill. Have saw it around 212 a time or two.

 

[aston4]

My Jeep didn’t have any pressure in the radiator when running when I bought it. Replaced the cap with a new one (went Mopar for it). A few days later the top radiator tank split. Cap hadn’t been sealing, probably for a long time, and the radiator was on its last legs. Once the radiator pressurized like it should, it split. Now have a new Denso radiator on it and it’s pressurized and keeping everything at the right temp.

Friend called me one day last winter. He was a few hrs from home and had a split in the top tank of his Toyota Camry radiator. I told him to take the radiator cap off and cut the seal on the cap to prevent pressure from building up. Then, top off the coolant and drive home. It was cold outside so not a lot of cooling capacity needed. Told him it’ll destroy your radiator cap but those are cheap and you’ll get home with no issues as the radiator won’t be pressurizing and forcing coolant out the top. Sure enough, zero issues getting home. Might have been an issue in the summer but not in the winter.

Pressurized radiators are a modern invention. Unpressurized radiators were the norm for a long time, but people got tired of having to refill with water or alcohol all the time, or forgot to refill and grashed the motor.

Unpressurized cooling systems were a lot safer. Pressurized cooling systems going bang have injurered and killed a lot of people. Don't ask me how I know.

 

[jjvw]

Pressurized radiators are a modern invention. Unpressurized radiators were the norm for a long time, but people got tired of having to refill with water or alcohol all the time, or forgot to refill and grashed the motor.

Unpressurized cooling systems were a lot safer. Pressurized cooling systems going bang have injurered and killed a lot of people. Don't ask me how I know.

Given how many millions upon millions of pressurized cooling systems have been rolling across the world for the past 60-70 years, I imagine they are quite safe in the grand scheme of things.

 

[aston4]

Given how many millions upon millions of pressurized cooling systems have been rolling across the world for the past 60-70 years, I imagine they are quite safe in the grand scheme of things.

Go work a burn unit for a while then get back to me. God bless the people that have the constitution to continue working burn units. Like the patients, the vast majority of the workers don't last long there either.

 

[jjvw]

Go work a burn unit for a while then get back to me. God bless the people that have the constitution to continue working burn units. Like the patients, the vast majority of the workers don't last long there either.

Ok. First, how many of those people are there due to steam burns? Then how many of those are there due to depressurizing radiaters?