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Discussion Starter · #1 ·
I am at my wit鈥檚 end!!!
New Heads, radiator, radiator fan, t-stat, all relays and penitential relays, temp sensor (twice 1st with Napa and 2nd with Mopar.
Verified the water pump and pulley are working properly and I鈥檓 still over heating with no indication in dash!?!?
Fan is working 馃憖
The only thing I can think of next is CPU? Any suggestions
 

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2006 TJ Rubicon, 4.0, automatic
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What is making you think it鈥檚 overheating if you aren鈥檛 getting any indication on the dash? If it鈥檚 boiling have you pressure tested the radiator cap?
 

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Right, check cap first, and on my wife's I bought hoses from O'Reilly's Auto that were specifically made for her '07 3.8 JK Rubicon that were collapse proof so when turned off, after driving & cooling, they wouldn't pinch closed........
Kevin 馃憡 馃憡 馃憡
 

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I am at my wit鈥檚 end!!!
New Heads, radiator, radiator fan, t-stat, all relays and penitential relays, temp sensor (twice 1st with Napa and 2nd with Mopar.
Verified the water pump and pulley are working properly and I鈥檓 still over heating with no indication in dash!?!?
Fan is working 馃憖
The only thing I can think of next is CPU? Any suggestions
I have an old beater TJ that used to do the same thing on hot days. It would be fine while I was driving then after I would shut the motor off it would boil and puke out antifreeze. I bought the lowest temp thermostat I could find and drilled a 1/16 inch hole through it to just insure there would be a balance of pressure. I know, don't flame me. Never had another issue.
 

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Discussion Starter · #11 ·
Ok. In post 1 you said that you weren't seeing any indication on the dash saying it was hot so what is it doing that makes you feel it's too hot? Fan going high speed? Boiling over?
The fan seems to be working but it doesn鈥檛 sound as ramped up as before.
No indications or alarm, it will boil and bubble feeling up the overflow and continue for a solid 5 minutes after shut down! Literally everything in the cooling system is new except the ECM .
I have hade her on ramps to bleed air hell I even sent it to the dealership and they haven鈥檛 a clue
 

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The fan seems to be working but it doesn鈥檛 sound as ramped up as before.
No indications or alarm, it will boil and bubble feeling up the overflow and continue for a solid 5 minutes after shut down! Literally everything in the cooling system is new except the ECM .
I have hade her on ramps to bleed air hell I even sent it to the dealership and they haven鈥檛 a clue
Yeah, that sounds like an issue with the cap or how the cap seals to the radiator neck. Or it could be the water pump isn't pumping water.
Even when everything is fine, the system runs at temps near or above the boiling point of water. The system relies on the cap sealing and pressurizing the system to raise the boiling point of the fluid. If the system can't hold that pressure, it will boil over without actually overheating. That sounds like what you have. The fan isn't running hard because the system isn't hot enough to tell the fan to run hard. And it isn't triggering high temp alarms in the system because the temp isn't that high. But due to the lack of pressure the system boils over.
 

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The fan seems to be working but it doesn鈥檛 sound as ramped up as before.
No indications or alarm, it will boil and bubble feeling up the overflow and continue for a solid 5 minutes after shut down! Literally everything in the cooling system is new except the ECM .
I have hade her on ramps to bleed air hell I even sent it to the dealership and they haven鈥檛 a clue
Are you using the proper 50/50 mix of coolant?
 
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