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Has anyone replaced a thermostat on the 2017 3.6L Acadia? I am experiencing temp pegged on cold, no A/C, cooling fan running all the time with P0128 code stored. Looking for location of thermostat and estimate on difficulty. Having to ask where the thermostat is located is already a bod start.
 

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I would be pretty surprised if a thermostat went bad already. Usually even if they get stuck open the engine will build some heat. When cold check to make sure it is actually full of coolant. At idle feel the radiator hose and see if it is getting warm. Maybe a bad sensor. It is interesting that the cooling fan is running all the time and you have no AC. I think you have something else going on there.
 

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I'm pretty sure thermostat is the culprit. Even after extensive driving if you held your hand behind cooling fan, drawing nothing but cold air through radiator. As you said, you'd think there would be some heat in the cooling system but there is none, therefore pegged on cold on the guage. A bad sensor would be telling you cold but system would really be hot. Not the case. I have seen some other posts where fan running and no A/C are the common symptoms. Evidently with the P0128 code, the system goes into a safe protection mode and eliminates heat creators and makes sure you have cooling. As far as surprised to think a thermostat is faulty at this early time (38K on vehicle), would you be surprised if I told you I've already replaced an E-Brake control module, a front strut, a battery and the worst set of worn out Michelin tires I've ever owned (tires at 26K)? A thermostat is just the next thing that you're working on that you shouldn't be. Really disappointing because the Acadia is a nice vehicle and a great road car, especially with the V6.
 

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Check out the thread below. Sounds just like what you have going on and someone with a 2017 had the same issue. Sorry to hear about all your trouble with your vehicle. We just traded our 2018 equinox and only got 20k miles out of 60k mile Michelins. All manufactures seem to be struggling with issues right now. And in some cases bigger stuff that leaves you walking.

 

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Thanks for the heads up. Looks like an easy and inexpensive enough repair. I'll probably go ahead and replace the temp sensor just for good measure. Can't hurt and might even do some good..
 

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Has anyone replaced a thermostat on the 2017 3.6L Acadia? I am experiencing temp pegged on cold, no A/C, cooling fan running all the time with P0128 code stored. Looking for location of thermostat and estimate on difficulty. Having to ask where the thermostat is located is already a bod start.
You probably already had it replaced but could you tell me about how much it cost. I just got an estimaate of $900! Evidently it is lacaterd beneath the manifold and part of the fuel injection has to be removed. Is this true?

Thanks

Jim
 

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Jbilco, what year? You may have the 2017- as this thread says 2017.
But the 1st gens, neither the manifold or fuel injection has to be removed.

pictures of its location here/
 

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I'm pretty sure thermostat is the culprit. Even after extensive driving if you held your hand behind cooling fan, drawing nothing but cold air through radiator. As you said, you'd think there would be some heat in the cooling system but there is none, therefore pegged on cold on the guage. A bad sensor would be telling you cold but system would really be hot. Not the case. I have seen some other posts where fan running and no A/C are the common symptoms. Evidently with the P0128 code, the system goes into a safe protection mode and eliminates heat creators and makes sure you have cooling. As far as surprised to think a thermostat is faulty at this early time (38K on vehicle), would you be surprised if I told you I've already replaced an E-Brake control module, a front strut, a battery and the worst set of worn out Michelin tires I've ever owned (tires at 26K)? A thermostat is just the next thing that you're working on that you shouldn't be. Really disappointing because the Acadia is a nice vehicle and a great road car, especially with the V6.
My 2017 Acadia is doing the same thing. Everything I have found leads to the Engine Coolant Temperature Sensor. It isn't hard getting to the sensor, but can't figure out how to get it out. I think I have to remove the Thermostat to get a socket or wrench on the sensor. Does anyone know if I have to drain the coolant before opening the thermostat? If I just have to drain a little, where should drain it from?
 

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My 2017 Acadia is doing the same thing. Everything I have found leads to the Engine Coolant Temperature Sensor. It isn't hard getting to the sensor, but can't figure out how to get it out. I think I have to remove the Thermostat to get a socket or wrench on the sensor. Does anyone know if I have to drain the coolant before opening the thermostat? If I just have to drain a little, where should drain it from?
Lower radiator hose is generally best.
 

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... Does anyone know if I have to drain the coolant before opening the thermostat? If I just have to drain a little, where should drain it from?
Disconnect the lower radiator hose at the radiator. Drain all the coolant you can and replace it with new coolant after you put everything back together. Be sure the new coolant is a 50/50 mix of Dexcool and clean water. Tap water is OK, but distilled water may be better if you suspect a high mineral content in the tap water. You can purchase coolant pre-mixed 50/50 if you want to do that.
 
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Has anyone replaced a thermostat on the 2017 3.6L Acadia? I am experiencing temp pegged on cold, no A/C, cooling fan running all the time with P0128 code stored. Looking for location of thermostat and estimate on difficulty. Having to ask where the thermostat is located is already a bod start.
I was charged $1400 for this repair with that code
 

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WOW!!!
$1400 for the thermostat.
I had no idea that is what the repair runs at the dealer.
 

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I am glad the newer LGX engine has a better designed thermostat location easier to access and replace if required.
 

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Does anyone know where I can get a replacement thermostat? I have a 2019 GMC Acadia V6 with 60,000 miles with same issues as everyone else. Steering assist reduced, no AC, gauge drops to cold and fan is blowing on high. We have already replaced the sensor and it still does it. Next step is going to be battery and thermostat but we cant find a thermostat ANYWHERE.
 

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Does anyone know where I can get a replacement thermostat? I have a 2019 GMC Acadia V6 with 60,000 miles with same issues as everyone else. Steering assist reduced, no AC, gauge drops to cold and fan is blowing on high. We have already replaced the sensor and it still does it. Next step is going to be battery and thermostat but we cant find a thermostat ANYWHERE.
What part are you looking for?

I believe the part number is GM 12678779. A quick goggle search shows it not very hard to find.
 

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Does anyone know where I can get a replacement thermostat? I have a 2019 GMC Acadia V6 with 60,000 miles with same issues as everyone else. Steering assist reduced, no AC, gauge drops to cold and fan is blowing on high. We have already replaced the sensor and it still does it. Next step is going to be battery and thermostat but we cant find a thermostat ANYWHERE.
You're right. I've looked for 2018, 2019 "water outlet" and thermostat . So far every place says out of stock or not available.
 
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