Jeep TJ Overheating issues Explained

[@charleshodge1873]

If you own a Jeep TJ I’d recommend using ONLY the MOPAR dealer radiator. Believe it or not, some aftermarket radiators LOOK ok, ...they simply don’t cool as well. I know this from experience. If you live in hot climate areas, I’d also recommend ventilation of the engine compartment via hood louvers/ vents. The TJ (& 4.0 in-general) are also susceptible to “fuel-boil” at the injector fuel rail. There is a foil insulation blanket on top of the intake manifold that is SUPPOSED to block heat rising from the exhaust manifold below,..but that blanket can become rotten, oil-saturated, etc.. which makes it ineffective.

[@TestDontguess]

I’ve used a cheap Rockauto 80 dollar radiator for the past 4 years and it’s been awesome

[@charleshodge1873]

BSK Garage I hear you,..BUT I tried various different copper/brass & aluminum radiators over the years in Texas, & none cooled as well as the MOPAR “plastic can” radiator. The very first thing I did after getting my 2003 TJ was replacing/upgrading the cooling system as it already had over 100,000 miles on the odometer. Water Pump, hoses, radiator, thermostat,...EVEN the fan clutch. I never had a problem with overheating until I replaced the old but apparently still ok radiator with a new four core copper/brass radiator. After that, I had issues at any rpm above idle that were only resolved by installing the original equipment MOPAR radiator.

[@mariodesmo]

@@charleshodge1873 - A buddy of mine had the same thing happen to him. Replaced the radiator with a Mishimoto and had nothing but problems. We went back to the factory radiator and had no more cooling problems. He's also in Texas.

[@thebowwowwow781]

Hey Charles, my jeep is 99 wrangler. The temp was over 260. Don’t think it’s a fan issue. Opened up the engine and some oil all over my intake and top of the hood

[@michaeladams3851]

Have 98 wrangler 2.5, flushed heater core. Still no heat, when trying to circulate the coolant in order to burp the system. Noticed when throttle the engine, water level in rad only pulls down slightly, doesn't look like actually moving. Could this be the fins on water pump?

[@mauricio5763]

Hi my coolant doesn’t seem to be recycling. I have a 97 tj 2.5l. I took the cap off and turned it on to burp after refilling and after most bubbles came out now it’s just pushing up slowly as it warms up. Water pump is bad maybe? I need help, thanks.

[@GBV1436]

Hi Jerry, could you explain more about how to tell if your radiator cap is staying pressurised?

[@1990lumina]

If the hoses are soft after driving it's prob not pressurized. You can test the cap too with a tool but I'd say if in doubt just replace it. Cheap insurance.

[@arizonacardinals6196]

If pressure leakm s thru the cap then there will not be enough pressure to open your thermostat and the engine will overheat

[@outlander7717]

what on your thoughts and large temp fluctuations on a 4 liter? mine will go to 210 then down to 180 back up and down 5 or 6 cycles until the motor has been ran for along time....then it seems to reach a homeostasis.

[@TestDontguess]

hard to say what the condition of your cooling system is, you can always try pressuring the system when it's cold to see if it holds

[@BrettHoustonTube]

Thanks What about having 3.07 gears with 32" tires? Will that cause the engine to overheat

[@mauricio5763]

You mentioned running lean heating up your engine. My 2.5l has been back firing more than usual lately and overheating as well. What should I look for as the cause to running lean? Thanks!!

[@joegonzalez8075]

97 jeep tj only runs hot on highway driving, any suggestions

[@mohammedjadallah3638]

I keep having overheating in my 03 jeep tj. I replaced the radiator thermostat water pump clutch fan head casket. I checked all the relay and its still overheated. I realized after i installed topfire style front grille i start to get overheat. I took it off, everything went back to normal. (It was not enough air flow to the radiator from the peice of crap i installed)

[@mariotibbrine1]

What about vibration dampener.

[@murphtahoe1]

Great info! Are you going to upgrade to a Mishimoto aluminum radiator and change to an electric fan for your LS swap?

[@TestDontguess]

Not sure all comes down to price and shipping

[@murphtahoe1]

Yeah...their pretty expensive!

[@Graveltrucking]

You will have to have enough cooling system going with an engine that has aluminum heads, temps stay rock solid at 190-200. Not sure if Evans coolant would work or not.

[@TestDontguess]

I have not decided if I’m going to try with the oem radiator or get a after market one yet

[@rabiebourchak2002]

Changed thermostat, radiator , new coolant ans still overheating any advice

[@jonc2914]

New radiator, new clutch fan, new thermostat, new water pump, new pullies and belt. Everything was fine, but then i got my ac fixed(new condenser) and i overheat when stopped at idle randomly(doesnt happens all the time) while driving, its fine even with ac full blast. No idea what the deal is... any ideas?

[@jonc2914]

I had a random overheat at idle... never happened again... any idea?😊

[@IntradeMotors]

Hey off topic that rear parking sensor from the onehanglow factory on your ford is that still functional?

[@TestDontguess]

Yes it is best seven bucks I ever spent

[@popo_53]

The louvered hood doesnt do dick for lowering coolant temps. Put one on my turbo LS TJ and it didnt drop temp but maybe a single degree.

[@jamesray3920]

Harmonic balancer worn out slipping also can cause over heating what about the floor getting very hot

[@definitionmedia1130]

Coolant temp sensor aswell

[@osvaldo8393]

Mine likes to go slightly above 210 and I wanna keep it at 195 but can’t lmao, I’ve replaced radiator , condenser, thermostat/ and housing, water pump , tensioner, I’ve applied the prestige coolant flush twice flushed the coolant , and flushed the system with distilled water and 2 more coolant flushes. And nothing I mean it stays at 210 on the highway but overheats ones it’s still, so I’m barely gonna do the fan clutch Now lmao

[@shansiddiqui3951]

Can you make a video on how to do a full coolant flush?

[@immersed9216]

you ever find a good video on the subject? Link pls.

[@denzpacitodenzybaby7116]

Does the TJ come with a condensor fan? Cause i know the XJ come with one

[@osvaldo8393]

No, only a mechanical fan

[@jonc2914]

New radiator, new clutch fan, new thermostat, new water pump, new pullies and belt. Everything was fine, but then i got my ac fixed(new condenser) and i overheat when stopped at idle randomly(doesnt happens all the time) while driving, its fine even with ac full blast. No idea what the deal is... any ideas?

[@arizonacardinals6196]

My TJ only overheats when I turn my a/c on and it goes back to normal when I turn it off. I dont know what causes that can anyone help

[@Michael-jp4oh]

Low refrigerant will do that.

[@arizonacardinals6196]

Michael matagrano it has new coolant clean radiator, cool wrapped headers and genrite side gills for air flow.. it ended up being clogged vents the air wasn't getting pushed out causing the ac to overwork itself

[@rickhenninger6978]

Thanks for the info

[@moabwheeling]

Great video Jerry . Hopefully that will help someone out if they are experiencing the dreaded overheating problem that a lot of 4.0 TJ 's experience. I for one have never had that problem (thank god ) however sometimes sitting at a light in the summer ( Utah ) my temp gauge will go from 210 to about 212 degrees. As soon as I start rolling again it goes back to 208 to 210 degrees. I'm adding a poison spyder hood vent this spring to help get rid of some of the under hood temps. Hope this helps ( don't see why it wouldn't ) with this . Take care !!

[@TestDontguess]

Poison spider hood best investment ever

[@MiguelGarcia-vj7oo]

cut the hood and put a gaudy ricer vent for only 2 degrees??.....lmao 🤣 what's next your gonna put a spyware app in your wife's phone because she smiled at the waiter?

[@danhambrick6331]

That LS will probably require more cooling capacity than that stock radiator can do...

[@TestDontguess]

Hard to say some people have had luck with the stock radiator

[@mauricio5763]

Hi my coolant doesn’t seem to be recycling. I have a 97 tj 2.5l. I took the cap off and turned it on to burp after refilling and after most bubbles came out now it’s just pushing up slowly as it warms up. Water pump is bad maybe? I need help, thanks.