Author Topic: JKU 3.6L Cooling Fan Issues  (Read 168 times)

Offline highlandercj-7

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JKU 3.6L Cooling Fan Issues
« on: June 02, 2021, 08:41:48 PM »
So I have found very little on this issue. I figured it's a long shot but I maybe one of y'all heard of this? My 2012 JKU 3.6L cooling fan is randomly going into high speed mode. The engine temps are remaining constant and nothing is over heating. I replaced the thermostat and housing and flushed and changed the coolant. The issue did not occur right after that, it tool several months so I doubt that has anything to do with it. I heard this Fan is a factory only unit and there is no after market support. It's a $400 is part so I don't want to toss parts at it without troubleshooting it first.
« Last Edit: June 03, 2021, 04:32:14 PM by highlandercj-7 »
HighlanderCJ-7

Offline dave2002ti

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Re: JKU 3.6L Cooling Fan Issues
« Reply #1 on: June 03, 2021, 06:41:46 AM »
Did you check Mopar Parts Online? They have the whole cooling fan module for under $450.

Dave Apker

Offline highlandercj-7

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Re: JKU 3.6L Cooling Fan Issues
« Reply #2 on: June 03, 2021, 04:34:51 PM »
I have not tried to buy the assembly yet. I just wanted to be sure I need it before I buy it. Sounds like it is something stupid because it works just not correctly.
HighlanderCJ-7

Offline mopar31898

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Re: JKU 3.6L Cooling Fan Issues
« Reply #3 on: June 03, 2021, 06:18:43 PM »
This is a total shot in the dark since I have a mechanical can on my TJ, could it be the temperature sensor or a relay that has gone bad?  Im not sure exactly how it is set up on the JKs but if the sensor thinks it is seeing a higher temp because it is malfunctioning, maybe it is kicking the fan to high more than it should.

Also, I assume the fan still runs in low sometimes, correct?

Sent from my Pixel 4 XL using Tapatalk

Offline zuke

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Re: JKU 3.6L Cooling Fan Issues
« Reply #4 on: June 04, 2021, 07:46:41 AM »
Are you confident it's running at normal temps? the guage is "buffered" Meaning it hovers right around the center mark at everything from 195 to 229. If you have the optional EVIC, it should give you a real temperature reading there.

If the fan works on both high and low speeds, I doubt it's defective.

When you change the coolant, do you remember seeing anything like grit, sand, or gel in the old coolant? There was an issue in 2012 with casting sand not getting properly cleaned from the engine blocks that lead to all kinds of weird issues.

If the temps really do hover around 205 to 215, and the thing is kicking to high speed randomly, i'd suspect a bad sensor..
John
2020 JT Sport S
2015 JK Rubicon
2015 JK Unlimited Sahara
2006 TJ Rubicon
1999 TJ HC Wheeler
1998 TJ SE

Offline highlandercj-7

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Re: JKU 3.6L Cooling Fan Issues
« Reply #5 on: June 05, 2021, 07:39:40 PM »
The jacked up part is the temp guage reads normal through this whole cycle. It does not fluctuate.
HighlanderCJ-7

 

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