Help needed: Jeep suddenly overheating after changing the thermostat
- Thread starter dukesilver24
- Start date
Sure could. Clearly, the coolant is not circulating properly. Another possibility would be a blockage somewhere, but that's less likely.
Could be a blockage if two different coolants were used that don't mix.
Do you mean the Mopar part number that i ordered feom the dealer or the faulty MotoRad stat PN?
I’m fearful of a blockage but I dont think that’s the issue. I can feel the fluid moving in the hose. I recently had it flushed and serviced at a local shop when we changed the stat the first time. If they used something non-OAT or all vehicle approved, i suppose that could be a problem. It ran fine for 4 days and then failed.
Thank you. That is the Mopar part number. Gonna try another dealership tomorrow. I’ll see if anything else comes up. Ty
This is gonna be long so hold on to ur shorts….
I experienced an under temp code so I changed the thermostat. (BTW anytime you put in a new thermostat, ALWAYS take it apart and work the action to ensure there is no factory gloss seal inhibiting it from opening on its virgin trial)
A week later I started getting overheating codes thrown. Tried several things to include new water pump, coolant flush etc… no bueno… was still getting super heated on the back side of the thermostat.
Had noticed a bit of oil in the coolant after the flush. Went back and looked at the coolant I had flushed out and there was oil in it as well. Checked the oil and thank the Lord above, no coolant in the oil. Did however find the valley between the heads full of oil and coolant mix.
Pulled everything down to heads and found slight seepage around 4 and 6 cylinders… bad juju.
Ended up pulling heads, which were warped and gaskets blown.
Milled heads put everything back together and still an overheat issue.
NOW FOR THE REAL ISSUE THAT CAUSED EVERYTHING TO CASCADE INTO MAJOR ISSUES:
The TCIP (computer mounted on the cooling fan) had malfunctioned well before the under heat issue. It was, unbeknownst to me, only running when the ac was on, thus overriding the tcip and coming on at low speed and quasi-cooling the engine.
Over a period of time, the engine was overheating somewhat on a daily basis… which later lead to the plastic oil cooler/filter housing in the valley to eventually crack and loose it’s seals, thus mixing oil and coolant on the coolant side.
This eventually led to a development of the heads overheating on a regular basis, which in turn led to warped heads and head gasket failure.
All is fixed now, but it was an expensive lesson learned about the JK 14 and later coolant fans.
IF YOU BEGIN EXPERIENCING OVERHEATING ON A 14 OR LATER JK:
Start the engine and get it to 225 degrees F. If the coolant fan does not kick in at precisely 225 F, replace the fan immediately. It will throw a code that does NOT set off the check engine light and will let you keep on driving with an ever increasing overheat issue that you simply don’t know about until catastrophic problems have already developed.
Hope my experience helps other JK’s 14+ out there
And yes, I replaced the oil cooler/filter housing with the aluminum Doreman housing to avoid the plastic sitting in the valley of heat death issue as well.
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Similar issues on 2015 wrangler. Bought it two months ago, been through two thermostats. Runs about 800 miles and then starts to run hot when climbing hills. Idling is fine, it never runs hot.
Hey TMan68 - thank you for the thoughtful reply. I really appreciate you taking the time to share your experience and I'm glad you got it fixed, albeit costly.This is gonna be long so hold on to ur shorts….
I experienced an under temp code so I changed the thermostat. (BTW anytime you put in a new thermostat, ALWAYS take it apart and work the action to ensure there is no factory gloss seal inhibiting it from opening on its virgin trial)
A week later I started getting overheating codes thrown. Tried several things to include new water pump, coolant flush etc… no bueno… was still getting super heated on the back side of the thermostat.
Had noticed a bit of oil in the coolant after the flush. Went back and looked at the coolant I had flushed out and there was oil in it as well. Checked the oil and thank the Lord above, no coolant in the oil. Did however find the valley between the heads full of oil and coolant mix.
Pulled everything down to heads and found slight seepage around 4 and 6 cylinders… bad juju.
Ended up pulling heads, which were warped and gaskets blown.
Milled heads put everything back together and still an overheat issue.
NOW FOR THE REAL ISSUE THAT CAUSED EVERYTHING TO CASCADE INTO MAJOR ISSUES:
The TCIP (computer mounted on the cooling fan) had malfunctioned well before the under heat issue. It was, unbeknownst to me, only running when the ac was on, thus overriding the tcip and coming on at low speed and quasi-cooling the engine.
Over a period of time, the engine was overheating somewhat on a daily basis… which later lead to the plastic oil cooler/filter housing in the valley to eventually crack and loose it’s seals, thus mixing oil and coolant on the coolant side.
This eventually led to a development of the heads overheating on a regular basis, which in turn led to warped heads and head gasket failure.
All is fixed now, but it was an expensive lesson learned about the JK 14 and later coolant fans.
IF YOU BEGIN EXPERIENCING OVERHEATING ON A 14 OR LATER JK:
Start the engine and get it to 225 degrees F. If the coolant fan does not kick in at precisely 225 F, replace the fan immediately. It will throw a code that does NOT set off the check engine light and will let you keep on driving with an ever increasing overheat issue that you simply don’t know about until catastrophic problems have already developed.
Hope my experience helps other JK’s 14+ out there
And yes, I replaced the oil cooler/filter housing with the aluminum Doreman housing to avoid the plastic sitting in the valley of heat death issue as well.
Bingo! The cooling fan module that is in the fan housing can go bad.
Big thank you to, BlackJKU and all others that helped get this 2015 Rubicon JK heating issue under control. As previously mentioned, we changed the stat 3 times, the coolant heat sensor, radiator, bled the stat, and burped it for days with no results. The jeep still overheated. As a last ditch effort, I took it to a local shop owner named Pee Wee in Wake Forest, NC. Pee Wee is awesome. He was emphatic that it wasn't the head gasket nor was it the cylinders. He had it for a couple of days and determined it was the cooling fan. While the fan seemed like it was working fine for me, apparently it wasn't running at full strength. He said the fan module inside the fan housing was failing. He tried to save me money by putting a non-OEM fan in it, but that didn't work so he put the OEM fan in it. We still had to burp the coolant system a couple more times, but all seems to be working as expected now. Thanks all!
Thanks for the update, and glad it fixed that problem. Why would they put a module in a fan housing in the hottest part of the front end.
Unfortunately it is integral to the fan, which is why they cost so much.
I found an aftermarket fan for about 400 bucks.
Update I replaced the fan and that started to work better, but now I have a back flow of coolant in the reservoir so I replaced the reservoir hose and the radiator cap. I also did a full drain and coolant flush/clean to get everything out and start fresh. I've burped it 4-5 times still getting air in the system every time i raise the front to burp it. The cap is a oem 18psi and I'm still overheating. I need help please
Either you're not getting all the air out, or air is getting back in from someplace. Start checking connections and seals.