TJ Overheating

[Ben Johnson]

Ok,
So I have been having overheating issues with my 02' TJ.
I flushed the radiator, changed the water pump and the thermostat.
I even put the "special" Chrysler coolant.
At highway speeds, I can get about 50 miles before my temp gauge starts to read hot and the dash light saying "Check Gauges" comes on.
My only solution is to turn on my heat, the gauge then drops and the light turns off.
The Jeep then runs great, but I have the heat blasting, which is annoying when its warmer weather outside.
Anyone have any idea as to what else I need to do to fix this issue??

 

[05 Blue Unlimited]

Ok,
So I have been having overheating issues with my 02' TJ.
I flushed the radiator, changed the water pump and the thermostat.
I even put the "special" Chrysler coolant.
At highway speeds, I can get about 50 miles before my temp gauge starts to read hot and the dash light saying "Check Gauges" comes on.
My only solution is to turn on my heat, the gauge then drops and the light turns off.
The Jeep then runs great, but I have the heat blasting, which is annoying when its warmer weather outside.
Anyone have any idea as to what else I need to do to fix this issue??

Fan clutch

 

[CodaMan]

Fan clutch

Agree

 

[Daryl]

If you remove the radiator cap can you see the ends of the core tubes? If you can what do they look like? Do you have air conditioning? If you do, check for debris build up between the a/c condenser and radiator. If the heating issue is only at highway speeds, it’s not the fan clutch.

 

[Ben Johnson]

If you remove the radiator cap can you see the ends of the core tubes? If you can what do they look like? Do you have air conditioning? If you do, check for debris build up between the a/c condenser and radiator. If the heating issue is only at highway speeds, it’s not the fan clutch.

The only thing is, I do have air conditioning, but I don't really use it.

 

[05 Blue Unlimited]

The only thing is, I do have air conditioning, but I don't really use it.

Daryl makes a great point. Using the AC or not is not a factor. It may be debris that has the air intake side of the rad blocked enough to prevent a proper air flow through the rad fins.

 

[Zac Oswalt]

Ok so I’m kinda having the same problem. Ive replaced the thermostat, and flushed my coolent. My engine ran fine up until about 15 minutes ago and I had to stop. I can’t use the heat technique because my heat won’t kick in and I’m about two hours from home

 

[Jerry Bransford]

Ok,
So I have been having overheating issues with my 02' TJ.
I flushed the radiator, changed the water pump and the thermostat.
I even put the "special" Chrysler coolant.
At highway speeds, I can get about 50 miles before my temp gauge starts to read hot and the dash light saying "Check Gauges" comes on.
My only solution is to turn on my heat, the gauge then drops and the light turns off.
The Jeep then runs great, but I have the heat blasting, which is annoying when its warmer weather outside.
Anyone have any idea as to what else I need to do to fix this issue??

Is the radiator a Mopar, aftermarket, or an auto parts store brand?

 

[AZ 4LO]

How's the fan clutch?

 

[Chris]

Maybe the fan clutch, but also check the radiator fluid level when the engine is completely cool and make 100% certain it's full. Had this happen to me once and it turned out to be the radiator was only half full. I forgot to fill it up all the way... doh!

 

[tjjohn]

Maybe you all can help with my sort of similar issue: overheating for a short period on the highway. My '98 TJ can do stop and go traffic all day, just below 210 degrees, but on the highway, 65 MPH or so, it will start to creep up. After sitting between 210 and the red line for awhile, it will then shoot up and the "Check gauges" light comes on. The needle will sit just at the beginning edge of the red zone, maybe 2 or 3 minutes, then drop back toward 210. This is not an immediate thing upon entering the highway, it takes some time to develop each time and will happen multiple times on a trip of extended time. The waterpump was replaced about 2 years ago and I've just replaced the lower radiator hose and thermostat. Doesn't lose coolant. I'm starting to think this may be an electrical issue, since the gauges have been temperamental before. Any ideas?

 

[Jerry Bransford]

That sounds like your thermostat is hanging up/getting stuck. I'd replace it with a fresh 195 degree thermostat like Stant's Superstat like at https://www.amazon.com/dp/B000C7YRNM/?tag=wranglerorg-20

Better auto parts stores like NAPA carry them, low-end auto parts stores like Autozone don't carry anything that good.

Whatever you buy make sure to not buy any thermostat labeled as "fail safe". While that sounds good, it's not... that type of thermostat tends to fail too easily in the open position.

 

[tjjohn]

I just replaced that on Monday. Had the problem before, and then took it on a freeway drive upon completion and it still did it. The thing is, in a traffic jam, the temp is fine, and when it does shoot up, it'll correct itself for awhile. What about the temp sending unit?

 

[Jerry Bransford]

Do you have an aftermarket or Mopar radiator installed? Have you ever wheeled in mud or similar conditions where the radiator fins could be clogged up with caked on dirt or mud?

 

[tjjohn]

It's the factory radiator, and it's clean.

 

[Dvaniwaarden11]

It's the factory radiator, and it's clean.

Old thread but did you ever figure out your issue? Sounds like my problem I have right now.

 

[LONGJP2]

Old thread but did you ever figure out your issue? Sounds like my problem I have right now.

He hasn't been around in a while.

Did you check your fan clutch?
Any recent service that may have induced air?
What's the coolant and/or radiator look like?

 

[Dvaniwaarden11]

He hasn't been around in a while.

Did you check your fan clutch?
Any recent service that may have induced air?
What's the coolant and/or radiator look like?

I’ve got a long thread on here and have been working with my mechanic that did my motor swap. We may have come to a solution with the clutch fan location. Some members on here mentioned it looked a little far outside the shroud. My mechanic called me today after I recommended that could have been an issue. Not sure what he did but he extended it further under the shroud and couldn’t get it it overheat after testing it for a few days. May have found the problem but once I get it back I’m going to run it through some more rigorous tests to see if I can make it overheat.