Overheating 3.8

Lmoye22

New member
Ok guys last resort before the dealership. My jk has been over heating under load. When I drive on the road that has elevation, my jk will heat up then the A/C shuts off and I loose a lot of power( limp mode). I have taken it to a shop who pressure tested the radiator and checked the head gasket. He says he doesn't know what else to check other than stripping it down. No charge due to not finding anything, he couldn't get it to over heat. Usually only happens when going over mnts or elevation. Replaced the thermostat with the same one. Replaced my radiator few months ago when it cracked. Just got the front axle replaced with a 44 due to bending the 30. I do have a tranny cooler up front as well. I don't know what else to do now. Thanks in advance!


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Ok guys last resort before the dealership. My jk has been over heating under load. When I drive on the road that has elevation, my jk will heat up then the A/C shuts off and I loose a lot of power( limp mode). I have taken it to a shop who pressure tested the radiator and checked the head gasket. He says he doesn't know what else to check other than stripping it down. No charge due to not finding anything, he couldn't get it to over heat. Usually only happens when going over mnts or elevation. Replaced the thermostat with the same one. Replaced my radiator few months ago when it cracked. Just got the front axle replaced with a 44 due to bending the 30. I do have a tranny cooler up front as well. I don't know what else to do now. Thanks in advance!


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Quick suggestion, Pull the radiatior fan off and check how dirty the radiatior fins are.
I had a similar dilemma because I live out west and our wheeling is a lot of sloppy mud.
Turned out to have a half inch thick wall of mud stuck between the fan and radiatior.
I'm not sure about your year, but my radiator also has a transmission cooler, and AC condensor infront of it along with a winch.
Doesn't get much air as is.
 
My WJ did the same thing and it was the fan clutch. Worked fine except in mountains. Also make sure the shroud is fully around the radiator with no abnormal gaps.
 
I've been thinking it might have been worse with the cooler. Mine is an 09 so the tranny cooler is an aftermarket. I also have a winch up front with the stinger. I live in far west Texas (El Paso). A few days ago it was in the 70's and I had no issues. Leaning more towards air flow. I will check the radiator again.


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I've been thinking it might have been worse with the cooler. Mine is an 09 so the tranny cooler is an aftermarket. I also have a winch up front with the stinger. I live in far west Texas (El Paso). A few days ago it was in the 70's and I had no issues. Leaning more towards air flow. I will check the radiator again.


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What size tires/gearing do you have?
Fan motor is a good suggestion as well.
OEM ones aren't waterproof (lol).
 
What size tires/gearing do you have?
Fan motor is a good suggestion as well.
OEM ones aren't waterproof (lol).

I'm running 35's with 5.10 gearing. I did replace the fan not long ago as well. I haven't been throwing parts at it lol just all those have broken along the way.


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I'm running 35's with 5.10 gearing. I did replace the fan not long ago as well. I haven't been throwing parts at it lol just all those have broken along the way.


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I'd definitely check if you had some blockage like I did then.
I couldn't tell by looking at, until i pulled the shroud off.
 
I've been thinking it might have been worse with the cooler. Mine is an 09 so the tranny cooler is an aftermarket. I also have a winch up front with the stinger. I live in far west Texas (El Paso). A few days ago it was in the 70's and I had no issues. Leaning more towards air flow. I will check the radiator again.


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09's have a stock transmission cooler. If you have AC, the cooler is at the bottom of your AC condenser. Lots of people have added an extra aftermarket trans cooler to help with some extra cooling capacity. I have an 08 and stock trans cooler was located at same place. I never added another cooler to the original transmission.


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09's have a stock transmission cooler. If you have AC, the cooler is at the bottom of your AC condenser. Lots of people have added an extra aftermarket trans cooler to help with some extra cooling capacity. I have an 08 and stock trans cooler was located at same place. I never added another cooler to the original transmission.


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I kept getting the hot oil warning when I was out off roading in the sand but with the extra cooler all has been fixed. One thing I have noticed is the floor board is getting a lot of heat now. A lot more on the passenger side


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Make sure all the air is bled out of the water lines since you said you just had the radiator replaced. I've had overheating issues on a few different vehicles due to air bubbles in the cooling system.

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if you replaced the fan you should check that it's operating like it should. Is it activating when the engine is running hot?

If you let it idle will the fan kick on?

you might check the fan relay to make sure it's operating properly
 
Make sure all the air is bled out of the water lines since you said you just had the radiator replaced. I've had overheating issues on a few different vehicles due to air bubbles in the cooling system.

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this ^^ as well, lift the front end of your Jeep on jackstands and with the radiator cap off, let it idle. if you see it bubble you've got air in the system, let it idle and slowly add some fluid until you see no more bubbles
 
I kept getting the hot oil warning when I was out off roading in the sand but with the extra cooler all has been fixed. One thing I have noticed is the floor board is getting a lot of heat now. A lot more on the passenger side


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Adding the extra cooler definitely helped some Jeeps. I got the hot oil message a few times, usually caused by climbing steeper trails/roads in to high of a gear. Sometimes it was necessary to run in 4 low, just to keep the RPMs up higher. This was a rare event for me. Never on the highway.


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this ^^ as well, lift the front end of your Jeep on jackstands and with the radiator cap off, let it idle. if you see it bubble you've got air in the system, let it idle and slowly add some fluid until you see no more bubbles

I did try this trick a few weeks ago but without lifting the front. I do remember having it bubble. Maybe it does have air. I'll try that tomorrow and try a thermostat from the dealer while I'm at. I'm wanting to plan a trip to big bend this weekend so we will see lol


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The fan is working great, it's does turn on. I have the super chips and I did make the fan turn on earlier due to the overheating. In the heat over the summer it got hotter faster. Usually just freeway driving on hills.


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I kept getting the hot oil warning when I was out off roading in the sand but with the extra cooler all has been fixed. One thing I have noticed is the floor board is getting a lot of heat now. A lot more on the passenger side


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Hot Oil is the tranny overheating & totally separate (and well documented) issue. You may have a couple of things going on....


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Took out some air from the system last night, just did a test run up the freeway going up the mnt and the jeep is still over heating. Thinking it's time for the dealership.


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