# New Thermostat Failing or Sensor or Other?



## downplay (Mar 13, 2017)

I am getting the apparently too common "AC Off Due to High Engine Temp."
But, the temp gauge shows cold and the engine didn't seem terribly hot.

Oh, and the fan is kicking on which it rarely does otherwise.

Which do I believe? The gauge or the computer?

It is a 2013 Chevy Cruze, dated 1/13 on the door, VIN: 1G1PA5SH0D7213581.

I just replaced the thermostat and thermostat housing because it was leaking
between them significantly. It seemed to be operating normally the last 2 weeks
until this morning. We haven't lost a drop of fluid but now this!

Is there a way to tell if it is just a sensor or if it is the new thermostat
failing? Or something else failing like the ECU?

I've read that older cars just would run cold if the thermostat is stuck open
and would burn up if stuck closed but I don't know how to interpret this newer
electronic engine!


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## Blasirl (Mar 31, 2015)

downplay said:


> I am getting the apparently too common "AC Off Due to High Engine Temp."
> But, the temp gauge shows cold and the engine didn't seem terribly hot.
> 
> Oh, and the fan is kicking on which it rarely does otherwise.
> ...


This might help: 2012 Cruze - Coolant sensor installation?


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## downplay (Mar 13, 2017)

Blasirl said:


> This might help: 2012 Cruze - Coolant sensor installation?


Yeah, I have both temp sensors on order at Oreillys, one for the radiator, and the one mentioned in the linked thread that goes into the thermostat housing. I hope a sensor is all that it is, they are not expensive, even together.

Any diagnostic suggestions are welcome!


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## Blasirl (Mar 31, 2015)

downplay said:


> Yeah, I have both temp sensors on order at Oreillys, one for the radiator, and the one mentioned in the linked thread that goes into the thermostat housing. I hope a sensor is all that it is, they are not expensive, even together.
> 
> Any diagnostic suggestions are welcome!


So far I have not had any issues, so I am collecting threads in case I do have issues in the future. There will be a bunch of dealer techs on probably tomorrow to give you more info.


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## aaron.terveen (Mar 30, 2017)

This?









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## aaron.terveen (Mar 30, 2017)

aaron.terveen said:


> This?
> 
> 
> 
> ...


https://www.carfax.com/processVin.c...ion_search=us&partner=OPR_0&search=Lookup+VIN

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## aaron.terveen (Mar 30, 2017)

https://www.vehiclehistory.com/vin-report/report-summary.php?vin=1G1PA5SH0D7213581

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## downplay (Mar 13, 2017)

I don't see how a car history report is going to help. My grandmother was and still is the first owner.

I also know now that it throws the error when it has been sitting long enough to be cold. Surely this must mean the new thermostat is not the fault. It must be electronic somehow.

In addition, I can see that the Dorman thermostat housing/thermostat I installed came with a new temp sensor already installed in the housing. So, it is only 2 weeks old.

It does look like to me that the wiring for the radiator sensor goes over to where the fan wiring goes. So, if the fan is automatically coming on, could this likely mean this sensor in the radiator has failed and is giving an automatic signal to the fan to run? And to the computer to complain?


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## downplay (Mar 13, 2017)

Is there no way to know which sensor, radiator or thermostat housing, is feeding the idiot gauge? I cannot find this information.


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## downplay (Mar 13, 2017)

Did I fix it!?! The computer doesn't complain now, the AC will turn on, and the fan runs appropriately instead of continually. The idiot gauge also work and stops right where it always used to, just a notch shy of half the dial. I hope so!

I replaced both sensors, the one in the radiator and the one into the thermostat housing. I was hoping I'd figure out which was the problem (if them) by replacing one at a time.

But, even after replacing both, nothing changed until I used my BlueDrive OBD II reader to clear the codes. If I'd known this, I would've tried clearing the codes first, and then again between replacing each sensor if needed, but, maybe you know how that hindsight thingy works!

Did I just need to clear the codes in the first place? Did I replace a failing part, and a good one, and then clear the codes to make it work? Do I have an intermittent problem that is going to rear its ugly head again? I don't know!

At least it looks like the thermostat is working perfectly for the moment. Is it possible for thermostats to work intermittently? They are simple mechanical devices, I wouldn't think so, but don't really know...


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## jblackburn (Apr 14, 2012)

The car probably was in a limp/safe mode of sorts because it didn't trust the readings from the temp sensors. Clearing the codes will tell it to reevaluate. It was likely only one of them, but should be good to go for a while now. 

The thermostat is sort of electrically operated. It functions like a conventional thermostat where it opens at temp, but it also has a heater that heats the wax ring to open it at lower temps if commanded to by the ECM

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## downplay (Mar 13, 2017)

jblackburn said:


> The thermostat is sort of electrically operated. It functions like a conventional thermostat where it opens at temp, but it also has a heater that heats the wax ring to open it at lower temps if commanded to by the ECM
> Sent from my SM-G950U using Tapatalk


Thanks for the new info!

BUT, it turns out it is not fixed. It operated fine for me last night but today it is giving the error again. I will just try putting the old thermostat back in as it wasn't the thermostat that was failing, it was the plastic thermostat housing. Maybe the car doesn't like the new Dorman thermostat. If I do that, everything except the housing will be Chevy or AC Delco again. A mechanic suggested I replace the thermostat because of the age and the fact that I needed to replace the housing, maybe that has been my downfall.

Oh, something interesting I found out about AC Delco, they market two different switches, one for the thermostat housing and one for the radiator under different part numbers and at a fairly big difference in price at Oreilly's. They look identical though, and there is a reason. If you look very closely at the numbers faintly printed on the parts once out of the package, they bear the exact same part number: 55591401. I can't believe I paid almost twice as much for one of them!


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## downplay (Mar 13, 2017)

So far, it seems I was right! I suspected the Dorman thermostat I installed mainly because the temp gauge seemed erratic, mostly it would take a crazy long amount of time to get up to proper operating temperature.

Now, I have replaced that thermostat with one from ACDelco and all seems normal now. No computer messages, no codes, and it is coming up to temperature quickly and on the mark like it always did in the past.

It'll take a few more weeks to be sure, but I'd suggest being suspicious of thermostats other than ACDelco, especially Dorman. However, I do like the metal Dorman thermostat housing (over the original plastic one) which is still installed and seems to be operating just fine.

If anything changes, I'll update, but I think it is fixed now.


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## winks79 (Dec 20, 2013)

I had the same thing to happen on my daughter's '13 LTZ/RS when it was about a year old. Just happened out of the blue one cold evening while driving down the road. When she got home, I could not find any symptoms of it running hot, or a reason as to why this happened. Cleared the codes, and it has never happened again. Been almost 4 years now. I have been told that sometimes the sensors will glitch and cause this issue, but if it continued after clearing codes that it would be a bad sensor causing the issue.


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## downplay (Mar 13, 2017)

We didn't have the problem until I fixed a coolant leak by replacing both the thermostat housing and the thermostat. I thought it was the sensors but it turns out the car didn't like the (brand new) Dorman thermostat. Clearing codes didn't solve the problem. So, I kept the housing but replaced the thermostat with ACDelco, and cleared the codes again. It has been driven nearly 200 miles now on long and short trips, AC on, AC off again, many times, and all seems to be working perfectly now.


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## Blasirl (Mar 31, 2015)

downplay said:


> We didn't have the problem until I fixed a coolant leak by replacing both the thermostat housing and the thermostat. I thought it was the sensors but it turns out the car didn't like the (brand new) Dorman thermostat. Clearing codes didn't solve the problem. So, I kept the housing but replaced the thermostat with ACDelco, and cleared the codes again. It has been driven nearly 200 miles now on long and short trips, AC on, AC off again, many times, and all seems to be working perfectly now.



Did you by any chance take some photo's? This could be a nice "How-To:" write-up. If you do this, make it a new post. You can reference this one in it if you like though.

FYI: I think the locations are the same on a 1.4 as well.


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## jpavlik (Dec 22, 2016)

I am actually having the same exact issue with my 2011 cruze. Had the "AC off due to high engine temps"....... replaced the 2 coolant sensors (1 in thermostat housing and one in radiator), cleared codes and immediately received a P0597 code. Figured I wouldn't mess around and replaced with Dorman Thermostat and housing 902-033. Light went off (didnt need to clear codes since this was done with the battery disconnect already). Drove the car for 50-60 miles and no issue. Drove for another 30 min or so to try and get the EVAP ready for emissions test, no luck. Figured just needs more driving. Next day, drive for hour and still no EVAP ready. Wife takes care to work no issues. Wife drives home from work and temp gauge starts bouncing. AC error again, then jumps to "HIGH COOLANT TEMP" and then "ENGINE OVERHEATED - IDLE ENGINE." She drives for another few blocks and all of a sudden the messages go away and the engine temp gauge drops to one tick below center on the cool side. I pop the hood, engine seems warm but no leaks, coolant still full and nothing out of the ordinary. 


What it seems like is the thermostat is staying closed and randomly releasing. Could this truly be a bad combo as you are saying? Or is it just 2 random bad Dorman thermostats? Or is there really another issue?

I drove it for another hour after messages were gone and it was fine while driving. I got caught in some traffic and it did the same thing described above. Last in total 3 min - 5 min. AC message came up, i drove a block. Engine overheat came up, drove another block. And pooooooof, all messages gone, engine temp back down. I will say the car did smell as if there was some overheating happening which leads me to believe that thermostat is sticking and once opens, all temps come back down. 

This just seems really random. Also, no check engine light during any of this. No codes during any of this.


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## marblerye (Nov 30, 2019)

jpavlik said:


> I am actually having the same exact issue with my 2011 cruze. Had the "AC off due to high engine temps"....... replaced the 2 coolant sensors (1 in thermostat housing and one in radiator), cleared codes and immediately received a P0597 code. Figured I wouldn't mess around and replaced with Dorman Thermostat and housing 902-033. Light went off (didnt need to clear codes since this was done with the battery disconnect already). Drove the car for 50-60 miles and no issue. Drove for another 30 min or so to try and get the EVAP ready for emissions test, no luck. Figured just needs more driving. Next day, drive for hour and still no EVAP ready. Wife takes care to work no issues. Wife drives home from work and temp gauge starts bouncing. AC error again, then jumps to "HIGH COOLANT TEMP" and then "ENGINE OVERHEATED - IDLE ENGINE." She drives for another few blocks and all of a sudden the messages go away and the engine temp gauge drops to one tick below center on the cool side. I pop the hood, engine seems warm but no leaks, coolant still full and nothing out of the ordinary.
> 
> 
> What it seems like is the thermostat is staying closed and randomly releasing. Could this truly be a bad combo as you are saying? Or is it just 2 random bad Dorman thermostats? Or is there really another issue?
> ...


Have you figured out the cause? I'm in the same boat and trying to avoid replacing more parts.


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## Sarahds3 (Jan 29, 2020)

Ok so we replaced one of the sensors that seemed to have taken care of it, yesterday I got the warning ac off due to high temps, no check engine light so I can’t see what code it’s throwing. Tonight on the way home I got the same message, I’m thinking maybe it’s the one by the radiator that’s going bad. Temp gauge says it’s cold like it will bounce between right above the first line of cold to the Second & then it goes back to cold. So should we replace the other sensor and see if that helps? I drive the 14 lt Model


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## jblackburn (Apr 14, 2012)

Sarahds3 said:


> Ok so we replaced one of the sensors that seemed to have taken care of it, yesterday I got the warning ac off due to high temps, no check engine light so I can’t see what code it’s throwing. Tonight on the way home I got the same message, I’m thinking maybe it’s the one by the radiator that’s going bad. Temp gauge says it’s cold like it will bounce between right above the first line of cold to the Second & then it goes back to cold. So should we replace the other sensor and see if that helps? I drive the 14 lt Model


Replace that one and bleed the system of air (there's a bleed screw near that one)


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## Miguelcon74 (Sep 2, 2019)

Make sure to get all air out of the system. That can cause it to think is hotter than it is.


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## BamaNYC (Jul 14, 2014)

marblerye said:


> Have you figured out the cause? I'm in the same boat and trying to avoid replacing more parts.





jpavlik said:


> I am actually having the same exact issue with my 2011 cruze. Had the "AC off due to high engine temps"....... replaced the 2 coolant sensors (1 in thermostat housing and one in radiator), cleared codes and immediately received a P0597 code. Figured I wouldn't mess around and replaced with Dorman Thermostat and housing 902-033. Light went off (didnt need to clear codes since this was done with the battery disconnect already). Drove the car for 50-60 miles and no issue. Drove for another 30 min or so to try and get the EVAP ready for emissions test, no luck. Figured just needs more driving. Next day, drive for hour and still no EVAP ready. Wife takes care to work no issues. Wife drives home from work and temp gauge starts bouncing. AC error again, then jumps to "HIGH COOLANT TEMP" and then "ENGINE OVERHEATED - IDLE ENGINE." She drives for another few blocks and all of a sudden the messages go away and the engine temp gauge drops to one tick below center on the cool side. I pop the hood, engine seems warm but no leaks, coolant still full and nothing out of the ordinary.
> 
> 
> What it seems like is the thermostat is staying closed and randomly releasing. Could this truly be a bad combo as you are saying? Or is it just 2 random bad Dorman thermostats? Or is there really another issue?
> ...


 I'm also having the same problem. Did either of you figure out what the problem actually was?


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## Erben311 (May 10, 2021)

Anybody get this figured out. I’ve tried troubleshooting it. I took it to a shop. They took 2 stabs at it. At a loss


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## Miguelcon74 (Sep 2, 2019)

Erben311 said:


> Anybody get this figured out. I’ve tried troubleshooting it. I took it to a shop. They took 2 stabs at it. At a loss


Needs to be an ACDELCO thermostat w/housing. 

Then you NEED to also make sure all air is bled out of system. 

One other possible issue is wrong psi coolant pressure cap. 

Needs to be 20psi. If it's less, it will cause this same issue.

Also any possible leak releasing pressure and/or fluid can have same issue.

Clear codes every time


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## Caitloglyn (Jan 6, 2022)

Having same issue on 2013… temp gauge goes up just a very little, Ac turn off and temp high shows but temp goes right back down… Trying to decide where to start!! Sensors? Thermostat? Also how do I clear codes?


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## jblackburn (Apr 14, 2012)

Caitloglyn said:


> Having same issue on 2013… temp gauge goes up just a very little, Ac turn off and temp high shows but temp goes right back down… Trying to decide where to start!! Sensors? Thermostat? Also how do I clear codes?


With a code reader. You can buy an OBD2 reader or Bluetooth module to connect to a phone on Amazon or auto parts stores. What codes are there? Any temp sensor or thermostat heater ones?


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## acasca (10 mo ago)

Hey everyone! 2013 Chevy Cruze 1.8L LS here with the same issues. Did some searching of my own initially when I first started getting the no reading on my temperature gauge and the AC off due to Engine Temp message. Replaced both temperature sensors on the engine & radiator. Gauge started reading again and didn't see the AC message for about a month. A side note, I also had a CEL with code P0598 -Thermostat Heater Control Circuit Low. Code never came back after clearing with new sensors.

To where I'm at now.
Temperature gauge is what starting acting up first again. Going from barely registering to not registering any temperature at all anymore. The fan is also on AS SOON as the car goes from off to on with the AC off due to engine temp message immediately. Got my car with 52k (at around 88k now) and i'm pretty sure the thermostat housing has already been done before I had it since the housing on there now is not the plastic junk, it's aluminium. It's weird because the coolant housing to the thermostat are sometimes barely luke warm and other times I check after driving the housing itself and the hoses are hot.

After reading into more forums and videos it's making me think my thermostat is getting stuck open here and there. Reason being the P0598 Thermostat Heater Control Circuit Low code.

Also after more of my own further inspection I did notice the temp sensor on the thermostat has a tear in the wire to the connector. The covering on top of the wire itself, not the actual wire to the connector. Could that cause any voltage issues? & When I say tear I mean i can see the wire (exposed) but the wire itself is not cut. Just not sure if the wire being exposed at all can cause voltage issues to the connector & the P0598 code.

I have a new complete thermostat assembly ready to be put on just wasn't sure if anyone else had any other ideas of what could be causing the issues.

Any help is greatly appreciated!


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## acasca (10 mo ago)

acasca said:


> Hey everyone! 2013 Chevy Cruze 1.8L LS here with the same issues. Did some searching of my own initially when I first started getting the no reading on my temperature gauge and the AC off due to Engine Temp message. Replaced both temperature sensors on the engine & radiator. Gauge started reading again and didn't see the AC message for about a month. A side note, I also had a CEL with code P0598 -Thermostat Heater Control Circuit Low. Code never came back after clearing with new sensors.
> 
> To where I'm at now.
> Temperature gauge is what starting acting up first again. Going from barely registering to not registering any temperature at all anymore. The fan is also on AS SOON as the car goes from off to on with the AC off due to engine temp message immediately. Got my car with 52k (at around 88k now) and i'm pretty sure the thermostat housing has already been done before I had it since the housing on there now is not the plastic junk, it's aluminium. It's weird because the coolant housing to the thermostat are sometimes barely luke warm and other times I check after driving the housing itself and the hoses are hot.
> ...


Ps. P0598 code is back as well.


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## jblackburn (Apr 14, 2012)

acasca said:


> Hey everyone! 2013 Chevy Cruze 1.8L LS here with the same issues. Did some searching of my own initially when I first started getting the no reading on my temperature gauge and the AC off due to Engine Temp message. Replaced both temperature sensors on the engine & radiator. Gauge started reading again and didn't see the AC message for about a month. A side note, I also had a CEL with code P0598 -Thermostat Heater Control Circuit Low. Code never came back after clearing with new sensors.
> 
> To where I'm at now.
> Temperature gauge is what starting acting up first again. Going from barely registering to not registering any temperature at all anymore. The fan is also on AS SOON as the car goes from off to on with the AC off due to engine temp message immediately. Got my car with 52k (at around 88k now) and i'm pretty sure the thermostat housing has already been done before I had it since the housing on there now is not the plastic junk, it's aluminium. It's weird because the coolant housing to the thermostat are sometimes barely luke warm and other times I check after driving the housing itself and the hoses are hot.
> ...


No temp sensor on the thermostat - one on the radiator, and one on the water outlet. . That wiring is for the heater that is built into the thermostats wax ring. That tear in the wiring is probably the cause of your code. You can probably buy the pigtail from a dealer and splice the new one in.


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## JLL (Sep 12, 2017)

AriaW said:


> I have a similar issue. Maybe the previous owner didn`t take care of it. Shall I check the car`s history?


Sure. I'd love to have my car's history checked!


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