I have a 04 Rubicon with an automatic. I have about 50K miles on it now. It runs great and temp is always right at 210. But when I lift the hood it just seems extremely hot! I can't hold the bar for holding the hood up or touch anything close to the radiator. Is this normal to have this much heat under the hood for a TJ?
Do you think it would hurt to drop the thermostat 5 degrees?
gen right makes an inexpensive set of 3 hood louvers that are positioned in the 2 hottest spots in your engine bay, just after the radiator and above the exhaust, the third is more of a symmetrical thing
yep its normal. Don't change the thermostat for a lower temp model, our jeeps were made to operate at 210. To reduce under hood temps you could look at installing a hood louver. I like the look of the poison spyder model. Unless you are having paint bubbling or engine overheating problems, i wouldn't worry about it.
__________________ The Wolf is not concerned with the opinion of sheep.
I had never noticed and read this post this weekend. I had an occasion to raise the hood today while it was hot and wow I could not hold the hood or the hood support rod. Going to put something on the support rod so I can use it even if it is hot.
I installed hood louvers. Two sets along the sides of the hood, and two at the right/left rear center.
They do lower the underhood temps somewhat when running on the road. However, I found that when I parked, the engine bay heat soaking was not relieved as much as I had hoped. I found engine bay temps rose from the normal 140F running temps to about 260F when parked. My engine bay heat sensor is located near the intake manifold, just above the exhaust manifold.
Since I had a spare electric 12-inch radiator cooling fan sitting around doing nothing, I installed it above the engine at the rear, supported by the two longitudinal engine bay rod braces running above the engine. This fan was positioned facing upward so that it blows hot engine bay air upward directly through the two center-rear hood louvers.
Because I only run the fan when the heat rises at the end of a trip, I also installed a timer that gives up to 15 minutes of run time after the engine is shut off.
Of course, if I were on a trail or heavy traffic and found the underhood temps rising despite the movement and radiator fan, I could turn on the engine bay fan for the additional cooling/air circulation.
In summary, with the hood louvers, I have found in 95F weather, the underhood temp does not rise more than about 140F running on the road, and when parked, if I run the engine bay fan for 10 minutes after shutdown, it rises only about 10 or 20 degrees above that, or to around 160F to 180F. After 10 minutes and the fan stops, the temps remain about at that level, so the 260F heat-soaking is avoided.
I'm not sure all this significantly benefits the underhood components. However, I have to believe it does some good to the engine computer, rubber hoses and belts, wiring, electric connectors, injectors, fuel rail, air conditioner, alternator, etc.
In any case, it makes me feel good, which is an important objective of any hobby anyway.
I have a friend with a Cheroke that is suffering from heat soak and he made some 1" blocks that mount between the hood and the hood hinge so the back end by the windshield sits above the body and he said it has helped but has not cured the problem. Just throwing it out there, to bad our TJ's hinges are different.
2004 RED TJ Rubicon
Member of the Gear Grinders 4WD Club
My engine runs hot and overheats only while running hard on the trail or pulling my single 4 wheeler on a small trailer. I made sure to clean all the mud from my radiator, put a 160 degree thermostat, replaced the fan clutch and still overheated. I've ordered a 3 row aluminum radiator and water proof electric fan. I will update once installed and tested.
Bad idea in the TJ's computerized engine. First, a 160 degree thermostat cannot somehow force an engine to run cooler in hot conditions... it will only force it to run too cool when in cold climate conditions. On a hot day, a 160, 180, and 195 degree thermostat will all be wide-open anyway so the fact a 160 degree thermostat might be present won't make any difference... the wide-open 160 degree thermostat can flow no more coolant than the also wide-open 195 degree thermostat does. If a lower temperature thermostat was all it took to run cooler on a hot day, we wouldn't need radiators... or we could get by with much smaller thermostats. Make sense?
Also, the engine computer is programmed around the factory specified 195 degree thermostat which is also the temperature the engine runs more efficiently at. Not to mention that low of a temperature thermostat can prevent the engine from warming up adequately on a cool day which would prevent it from passing a smog test.
I'd replace that 160 degree thermostat with the correct 195 degree thermostat and make sure NOT to install a fail-safe version which has a bad habit of failing all too often and sticking in the open position.
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Yeah. My hope was if it opened sooner it may take it longer to heat up. It hasn't set any codes like say P0128, coolant temp. below thermostat regulating temp, so not too worried about the computer but it doesn't help regardless.