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Discussion Starter · #1 ·
Hi, I have a 2011 3.6 GC and for the past month or two about every once a week or so my Check Engine light came on. It would turn off by itself a day or so later so I never checked it, until now.

This morning I have a P0128 for coolant temp being low. It has not gone away yet and I do not know if this is the same code as before, because I did not check.

Last Friday I installed the Diablo 93 canned tune and I know I read something about the fan staying on. Not sure if that is the issue this time. I am going to check anti freeze tonight.

Any other thoughts, besides replacing thermostat or sensor. And if it is those two what order to go in?

thanks

rob
 

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Hi Rob

I'm in the same boat, have the p0128 code maybe 1-2 times a week in the morning only. Going to look into replacing the thermostat first.
 

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Discussion Starter · #3 ·
Mine came back on yesterday driving down the highway with it being 70 or so very humid and therefore A/C was on. I don't use A/C much so not sure if tied to that or no. I might try thermostat as well soon. Let me know how it goes. I have 88k on car.

I see you have a lockpick. I have looked into that. I have the 730N RER radio and would like the ability to enter directions while moving, especially when the passenger is in the car. And also show album art and maybe use a USB for music playback instead of the ipod classic which works good but sometimes loses communication and can be finicky.
 

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I havent used ac in the morning for a while, just the fan, so not related.

Havent been able to find a pdf instructions on changing the thermostat on the 3.6 yet, please let me know if you do. I'm sure changing it is easy, I'm just worried about bleeding the system of air.

Yes love the lockpick, always travel with wife/kids, so much easier when she can enter directions. We have a sienna that we made some road trips in this year, and what a pita it is not being able to enter when you're moving...
 

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The same problem in my car. P0128 code. I just decide to replace the coolant sensor first. Then if the problem still existing I will replace the thermostat.
 

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P0128 sets when it takes longer than normal for the engine to reach operating temperature. Generally caused by a thermostat that is partially stuck open and/or low engine coolant.

If there is a problem with the coolant temperature sensor, there are several trouble codes that can set for that as well. ;)
 

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Discussion Starter · #7 ·
So Ratchet, in your opinion replacing t-stat would be the first option over the sensor?
 

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So Ratchet, in your opinion replacing t-stat would be the first option over the sensor?

The easy way in replacement should be the first option. As the cost approximately the same between the thermostat and sensor.
In my opinion, I will start replacing the sensor first.
Let's hear from Ratchet.
 

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rlefig: Yes, P0128 is thermostat rationality. I see this almost on a daily basis on these 3.6 engines. I would definately replace the thermostat first. The repair is very simple.

Note: There is no need to completely drain the engine coolant. You will lose a small amount during the thermostat housing R&R. However, there are a few specific steps that must be performed during the refill process. The steps should be available on WK2jeeps. If not, I can forward them to you.
 

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Discussion Starter · #10 ·
Thanks Ratchet, I will try and find the procedure on wk2jeeps. I have read that we need special coolant so of course get that as well. Any particular t-stat best for the 3.6?
 

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Discussion Starter · #11 ·
Also would the check engine light cause remote start to be disabled. The last couple of days have been cooler and when I attempt to remote start I see "remote start disabled on EVIC". It did work last winter. I will clear the code and try again
 

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Yep. If the MIL is on, remote start will be disabled.

Save yourself some headache and get the thermostat/housing from the dealer. Should be around $35.
 

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Discussion Starter · #13 ·
Thanks again Ratchet will get coolant and T-stat from dealer.

Hope you are all not in the flooding rain that has been occurring in the Carolina's
 

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No problem.
As for flooding, we got lucky this time. Only a few inches of rain fell here. Back in 99, my entire town flooded. Not fun wading through chest deep water in your living room. It can be fun to ride a jetski through your house though. :)
 

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Discussion Starter · #15 ·
Ratchet if you could forward me the link on t-stat changing from wk2jeeps that would be great. That is a good site never been there before
 

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After you have bolted up new thermostat... cliff note version.

-Remove bleeder screw on top of thermostat housing.
-Proceed to refill radiator with proper coolant mixture (50-50).
-Pause the refill procedure when a steady stream (no air bubbles) comes from the bleeder vent.
-Reinstall and tighten bleeder screw on thermostat housing.
-Continue to top off coolant level in radiator.
-Install radiator cap.
-Top off coolant level in recovery/overflow tank to the left of radiator.
-Start engine (make sure AC is OFF) and let idle untill it reaches operating temperature and electric cooling fan cycles on.
-Shut off engine and let cool for several hours.
-Top off coolant recovery tank if needed.
-Done.
 

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Discussion Starter · #17 ·
Thanks Ratchet,

Got the thermostat from dealer for $44 was going to get anti-freeze from there but it was $24 which seemed like a lot at the time. But now doing more research and seeing that the Zerex G-05 is really the only sub and that was $18 at local store then maybe $24 is not so bad.
 

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Discussion Starter · #18 ·
thermostat replaced, it came with the housing. Upon removing the old t-stat I broke the lower bolt. Luckily there was enough bolt left to PB Blast and vice grip it out. That process took about 2 hours as I wanted to be wicked (ok very) careful. Once I got that out it took about a gallon of coolant/water. I drained it some of it before hand which amounted to a gallon and 6 ounces. will check coolant level again.

Hope this fixes the P0128 code.

Thanks Ratchet and all who offered their time and advice
 

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No problem. Glad we could be of service to you. ;)
 

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Getting here late but for me the first thing would be to get a scan tool and find out what the temperature really is (with an Android tab or smart phone all you need is Torque Pro ($5) and a Bluetooth dongle ($12)). Then see what the radiator hose feels like (warm/cold/hot) when it comes on.

I'm thinking about changing to a 180F thermostat and am curious at what temperature the low temp error is set.
 
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