Sunnysideup

I'm just up the road from you! at least in our neck of the woods.... Anyway, my brother added some grill protector things that inserted into the grill slots... and his jk starting overheating after years of never once doing so... they were just enough blockage to create a problem... removed them and it went away. Other than that... you begin to wonder if it is plugged or has trapped air in the system. If the temp is climbing and everything is working and it used to work... something changed in the last 5 to 7 months. Does it drop the temp if you open up your heater at full blast? Full heat... just trying to help you think about where it might be clogged up? Or... it could be a bad pump... I replaced one and is was out in a month. Sometimes we overlook parts we just replaced... but they are bad from factory. Did you buy a Mopar pump? IF you have no luck with the thermostat... another random thing to check is the other belt driven pullies... maybe one of them is creating a drag? One thing is for sure... if it heating up this time of the year... the hot days of summer are gonna be really bad!

Adakar

Hi
I have a similar problem time ago
I try many things
To make a short story I have to work in the cilinder heads and replace all the gaskets with victor reinz brand.
Problem solved
Check if the coolant level dropsCheers

G.A.H

50/50 mix or you bought concentrate and mixed them yourself?? You can actually buy a toll and test your coolant if it's good and check the boiling temperature of the coolant if its low just add concentrate and if your coolant checks okay, turn your jeep on and let it sit for a while and keep checking if the temp on the upper hose is the same temp as the lower hose if the fan turns on and the top is still colder then its the thermostat if it's the same no problem there, next thing is to check for bubbles in the coolant wheb the jeep is cold open the cap and start the engine if you see bubbles coming out give it a little bit of gas more bubbles comes out then its the head gasket , if everything checks good then its the water pump, and if you think it's airflow then it's badly restricted in order to cause overheating which i doubt and if all checks good then its the radiator it's too small for the jeep or the fan not working properly but from what i read your fan is actually working properly and you have a mishimoto radiator which is actually a good brand. (If everything looks good then take it to a priest and ask him if he can quick those demons out )

tjkamp

That g-30 appears to be an OAT, so that shouldn't be an issue. How many miles on the Jeep?

When you were swapping everything out did you notice any sand in the bottom of the overflow tank? Is there any in it now?

I had the same overheating that you are describing, but I had had the casting sand in the coolant issue (prevalent on 2013s). I replaced everything, leaving the radiator for last. Then when I went to open the petcock valve on the bottom of the radiator, nothing came out. The bottom of the radiator was full of sand. Swapped out the radiator, no more issues.

I had the system flushed twice, trying to unclog my heater core, and it didn't do anything except cost me money. Never had any overheating issues, just a heater that blew hot as hell in the passenger side, and outside air temp on the driver. Then about two years ago, in the spring, it started over heating as you described. Heater core and the overflow tank and the bottom side of the radiator we're all full of casting sand.

JeepMateo

yeah, I cleaned the overflow bottle a while ago because of the casting sand being coated all over it. Heat blows hot everywhere. It’s got 135k miles

Found That there was coolant running down the back of the block and bell housing after pressurizing the system so was able to see where the leak is coming from, there is an oil cooler filter located underneath the intake. Replaced that and now no more leak, but still overheating at 5k rpm going 75 mph up a grade on the freeway.... I’m stumped

Mr.T

Did you check the tstat the way I mentioned in post 7?

barongan

subscribed, this seems like a very interesting thread

JeepMateo

yes, i couldn’t get it to open. And replaced it with a new one and couldn’t get that one to open in hot water either. So I took out the t stat and am now running no t stat and it’s still getting hot at 4500-5k rpm on the highway.

JeepMateo

Hey y’all, just took a trip this past weekend and so my Jeep gets hot, like up to 240-250 while going 75-80 on the freeway especially when going up grades in 3rd gear at 4500-5k rpm. Guys had told me that that’s normal at that rpm but idk as I posted A kinda similar question before but I just talked to a guy with a gladiator hauling a trailer and asked him if he had any overheating while pulling a 4500 lb trailer up grades on the freeway and he said no, even when the engine was screaming...Is it cuz of all the extra weight I have and tires and that my Jeep is like brick going through the air? I have replaced everything in the cooling system and have a free flowing t stat so it’s not any of those...any ideas?

Mr.T

Absent instruments to measure the actual temperature and compare, the temperature sender might be worth replacing. Perhaps it's reading ~15F high at that temperature.