# A/C off due to high engine temp, now overheating, see what I found



## snowwy66 (Nov 5, 2017)

Is the engine a reverse flow system. Never heard of something like that. I can't imagine water at the coldest point of radiator hitting the hottest point of the engine. Working it's way down to the coolest part of engine and back in to radiator.


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## Jon87transam (Sep 26, 2017)

I believe that it is. Reverse flow cooling is not new technology. GM used it consistently in performance vehicles as far back as 1992 with the introduction of the LT1 in the corvette. The 4th gen F Bodys (camaros and firebirds) started using LT1 in 1993 with the same cooling design. Starting in the 1997 corvette, the LS1 engine series also has reverse flow cooling. F-body's adapted LS1 in 1998. This style engine found it's way into the full size truck line starting in 1999. The reverse flow design allows for higher compression ratios and slightly more timing advance since the heads are getting cooled off first, and the Aluminum heads will dissipate the heat faster. it allows for a more constant temperature throughout the engine. The cooling system also incorporates the use of Dex-Cool, which I understand is designed to allow heat to transfer better than traditional green coolant. If a person were to look at GM radiator thicknesses throughout the 90's, you will see a movement towards thinner radiator cores as vehicle platforms move to Dex-cool which seems to support that statement. While this happened, the engine sizes remained the same, or increased. Sorry that was long winded, but wanted to give the history that I know. I was earning a living during the 2000's working on many 90's and 2000's model GM vehicles and owned many F-body's along the way.


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## CHEVYCRUZE RS (Mar 29, 2011)

Did you ever get a water pump recall on your cruze? Im not sure myself if the 2014's had this problem I know a bunch of people with 11's and 12's who had terrible water pumps.


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## Jon87transam (Sep 26, 2017)

No, the water pump has not been replaced to my knowledge. i cannot find a leak by look or feel in or around the water pump. i regularly check this area though. i believe the water pump is under warranty from GM for 150,000 miles.

Also, a small update on my project. i disassembled my old thermostat to see how it is made. At first, i thought it might have been entirely electrically operated by the PCM, but i now understand that it still has a thermospring with some sort of PCM operated heater circuit. i do not fully understand how the thermostat pulls itself open, because the thermospring is not attached to the sealing disk. As I reviewed the pieces of the thermostat, the actual operation of opening and closing was extremely tight, even after disassembly. i had to use tools to get the valve to open and close. Again, the spring was not installed, so I feel like the operating of the inner valve should have been smoother and easier. I do feel like that the thermostat is what has been causing all my issues. I believe it is sticking open, or sticking closed. 
Obviously, I am going to replace the thermostat anyway. I will be using a MotoRad brand thermostat instead of the OEM (or AC Delco). The MotoRad has a slightly different look to it compared to all the other possible options that I have found. This may or may not be a mistake, but I want to try it. I have had good service with MotoRad products in the past. Since the OEM only lasted barely past 50,000 miles, I don't have a lot of faith in another OEM replacement. 



























I also removed the new coolant temp sensor that I installed on the cylinder head side just last week. i wanted to see how it checked out with Ohm readings compared to the 2 OEM temp sensors that were in the car. All three had different readings sitting on the table. I still want to use 2 new "gold" terminal sensors, and i was very surprised to see the NAPA replacement i previously purchased had the gold terminals. I decided to purchase another identical temp sensor (NAPA TS5839) and use them when i reassemble the car. I picked up the second NAPA sensor and tested the 2 NAPA sensor against the 2 OEM out of my car. There was definitely a larger spread in the difference of Ohms between the 2 OEM and the 2 NAPA sensors (.25 ohms vs. .05 ohms, respectively). This may not be enough difference between any of them to make any difference at all. Never the less, I am moving forward with my plan, good or bad. When the thermostat arrives, I will reassemble the car and see what happens. I will keep you posted.


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## Jon87transam (Sep 26, 2017)

well, i tried to post an answer, but it never appeared. i'll try again...

No, as far as I know, my car still has the original water pump. I do check this area often. It is clean and dry with no leaks of any kind. I know it is warrantied until 150K. I figure as soon as I get the cooling system straightened out, the water pump will take a dump. That's how this stuff works.

I took apart my original thermostat. I was under the impression that it was completely electronic. However, it has a thermospring just like any other thermostat. It incorporates some sort of heater in the thermostat, and i don't exactly understand this function. The thermospring is not directly attached to the valve disc . So when the spring starts to heat up and draw back, I don't understand what actually pushes the valve disc back to allow coolant through. When I tested the operation of the internal parts by manually opening the valve, the operation was very tight and required me to use tools to pry it open. the closing action was very tight and rough as well. I assume my issues of the "AC off due to high engine temp" was caused due to the thermostat sticking open, and the overheating issue caused by the thermostat sticking closed. I doubt either of the coolant sensors are to blame, but I don't have a scanner to verify. I am replacing the thermostat with a MotoRad brand unit. It has a slightly different appearance than all of the replacement options I can find. I have had good luck with MotoRad in the past. I don't want to use another OEM unit, or OEM look-a-like as I only got 54K out of the original. This may or may not be a mistake, but that's my plan. Personally, I feel it is totally pathetic that a thermostat can only last about 50k miles before it craps out. I know this is far from an isolated case with this car / engine. 

I "tested" the original coolant temp sensors with an Ohm meter, and they test within about .20 to .30 Ohms (on 20K scale) when compared to each other. Again, one sensor has the tin terminals, and the other has the gold terminals. i checked the NAPA sensor that I purchased previously, and surprisingly it has gold terminals. The part number is TS5839. Since my original plan is to use gold terminal sensors, I decided I would purchase another TS5839 and test the Ohms against each other. I found a much smaller spread between the NAPA sensors. Around .05 to .07 Ohms (on 20k scale). I'm not sure either comparison is enough to warrant any concern. However, I am moving forward with my plan and going to use the NAPA TS5839 for both locations and see what happens. I'll keep this thread posted as I reassemble and drive the car for a few days. Right now, I'm just waiting on the thermostat, belt, and air filter to arrive so I can put it all back together. 

At this point, I have only put about 6000 miles on this car. I have had to have the Intake Manifold replaced, Valve Cover replaced, Cam Actuator replaced (oil leak), and Spark Plugs changed. The previous owner had the steering rack replaced, ignition coil pack replaced, and brake booster replaced. Now the thermostat is getting replaced. The original belt was making an awful noise also, so it is getting changed out as well. At 54000 miles, i am officially ashamed I purchased yet another GM vehicle. This was the last chance of owning a GM vehicle past model year 1999. I have owned 32 vehicles so far, and most have been GM products. As a side note, none have been new. Nevertheless, I am done with the GM brand after this experience. I will probably sell the car and just move on. At least the next owner will have until 100,000 miles to have the engine fixed under warranty. Anyway, I'll keep you all posted.


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## Jon87transam (Sep 26, 2017)

I have installed the parts I listed above. New MotoRad thermostat, 2 new NAPA coolant sensors (TS5839). I've driven the car a little over 500 miles, I've had no problems...so far. At the same time, I also decided I didn't like the 20lbs radiator cap. I figured out how to take the cap apart and finally got to the pressure spring. I trimmed 2 coils off the spring and re-assembled the cap. It seems to me that 20lbs is very high, and I decided I would see if it could be reduced. I'm not sure if I accomplished anything, but theoretically that should take just a little pressure off. It's no wonder these engines are prone to "weep" coolant running that high of pressure. I will keep this thread updated if there are any more issues that come up. Hopefully I can just drive this thing for a while before something else fails. Time will tell...


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## snowwy66 (Nov 5, 2017)

I"m pretty sure the reason for the high pressure is the fact that temps run pretty hot. 

220 degrees is going make higher pressure as it's boiling more then 190 degrees. 

And while i haven't seen what the thermostat looks like yet. The way to check if it's working properly is to stick it in a pan of water and heat it up. You need a thermometer to measure the water temp and watch for thermostat to open. I don't own a gen1 but from the posts on this sight. Looks like it opens at 221 degrees. 

I"m not sure if that method can still be used though on the newer thermostats.


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## Jon87transam (Sep 26, 2017)

it's been a while, thought i would update this post. 

i tried to upload pics of the OEM thermostat disassembled. i hope they got attached.

At my last post, i had driven 500 miles with no issue. I should have waited a little longer to update the post. After reaching around 800 miles, i again received the "Engine Off due to High Engine Temp" message and lost my temp gauge. My cooling fan also kicked to High. I continued my drive to work which was about 70 miles from the point of the message, with no other issues. During my lunch break, I visited the local GM dealer (good reputation) and told them what was happening and asked about TSB's (the message was still on the dash at cold startup during lunch). The service writer couldn't find any open TSB's for 2014 regarding this issue, but commented they had a similar issue with a cruze a week or two back and replaced the thermostat and cleared the codes, and seemed to have fixed the problem. I explained all the items I had replaced to remedy my issue and he seemed surprised I started having trouble again. 

I returned to work and found a 10mm socket and ratchet, removed the battery cables and touched them together. This cleared the message, it asked me to roll down then roll up the driver window upon first startup, and the gauge came back to life. I shut off the car, got ready to close the hood and just happened to look at the negative cable and where it attaches to the radiator support. I took my tool and tightened all the ground connections, and shut the hood. I have driven the car about 3000 miles since I did all of this, and I haven't had the message re-appear...yet. I am going to remove all those ground connections and clean them and re-install along with the one I see on the strut tower. i will look for any other grounds I can find and do the same. I don't know if this really makes any difference, but it's worth a shot. 

snowwy66: I totally understand what you are saying about the increased pressure related to high temps. So far, I can't determine that I have caused any harm in trimming the spring inside the coolant cap, but it is also not warm temperatures yet. Worst case scenario is I have to buy a new cap. This shouldn't be an issue as it appears I will have plenty of opportunities to visit a parts store while owning this vehicle. 

Again, I will keep this post updated for a bit to let you know how this issue is coming along. I do know I'm going to buy a ratchet and socket to keep in the car so I can remove the battery cables and clear the message if it comes up again. If I keep having trouble down the road, I may try a re-flash at the dealer. 

It also seems weird to me that many GM vehicle platforms are experiencing the "Engine Off due to High Engine Temp" message. If you search the message on google, you will find other GM platform forums trying to figure this out as well. I don't think it is isolated to the cruze at all. Not that this really matters to me, as I am finished with GM in regards to anything past the late 90's. 

I'll keep you posted


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## Taxman (Aug 10, 2017)

Jon87transam said:


> I also decided I didn't like the 20lbs radiator cap.


You dislike it more than you dislike boiling and cavitation?



snowwy66 said:


> I"m pretty sure the reason for the high pressure is the fact that temps run pretty hot.


Indeed. Isn't 230 degrees considered normal operating temp these days?


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## Jon87transam (Sep 26, 2017)

I'm not concerned with boiling or cavitation at this point. Even if I lost 5lbs of pressure by cutting 2 coils off the coolant cap spring, that would leave the boiling point of 50/50 dexcool and water at around 265 degrees at 15psi. Would those 2 small coils equal 5 psi? No idea. Personally, I feel like the cooling system is better served by losing 5psi of pressure to prevent leaks and retain the coolant than trying to raise the boiling point over 265 degrees. The cooling system isn't worth much if there isn't enough coolant in the system due to leaks.

I need to test the cap to see what exact pressure it is at now. Again, the worst case scenario is that I need to buy a new coolant cap. And, in the slight chance i damage the engine, I still have 40k left on my powertrain warranty.


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## mikestony (Jan 17, 2013)

So there are 3 temp sensors correct? One in the thermostat housing, one in the water outlet, and one on the lower side of the radiator?


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## snowwy66 (Nov 5, 2017)

Indeed. Isn't 230 degrees considered normal operating temp these days?[/QUOTE]

No. The gen1 cruzes are the first car I've heard running that hot. 

Imports are running around 175. The americans seems to be at 185, including the gen2 cruzes. 

230 degrees is insanely hot. That's dangerously close to meltdown.
@Taxman


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## snowwy66 (Nov 5, 2017)

Jon87transam said:


> I'm not concerned with boiling or cavitation at this point. Even if I lost 5lbs of pressure by cutting 2 coils off the coolant cap spring, that would leave the boiling point of 50/50 dexcool and water at around 265 degrees at 15psi. Would those 2 small coils equal 5 psi? No idea. Personally, I feel like the cooling system is better served by losing 5psi of pressure to prevent leaks and retain the coolant than trying to raise the boiling point over 265 degrees. The cooling system isn't worth much if there isn't enough coolant in the system due to leaks.
> 
> I need to test the cap to see what exact pressure it is at now. Again, the worst case scenario is that I need to buy a new coolant cap. And, in the slight chance i damage the engine, I still have 40k left on my powertrain warranty.


Boiling point of 50/50 is roughly 223 degrees. 

According to google. Every pound of pressure in the radiator raises the boiling point 3 degrees.


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## TDCruze (Sep 26, 2014)

snowwy66 said:


> Boiling point of 50/50 is roughly 223 degrees.
> 
> According to google. Every pound of pressure in the radiator raises the boiling point 3 degrees.


I can attest that mine did not boil at 260F with 60/40 mix and a 20psi cap. This still does not mean it was good for the engine.

My Cruze does not even turn on the high temp warning light until about 260 for some reason.

I would think that somewhere closer to 240 would be a safer warning threshold and give the driver more time to get off the road safely. I was in a panic when my light came on, but I had a gauge and was already working on getting off the road when the warning came on.


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## Jon87transam (Sep 26, 2017)

snowwy66 said:


> Boiling point of 50/50 is roughly 223 degrees.
> 
> According to google. Every pound of pressure in the radiator raises the boiling point 3 degrees.


Sounds about right, so at 15lbs would be around 268 degrees boiling point, which Zerek and Prestone claim 265 degrees for 50/50 dexcool.


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## Jon87transam (Sep 26, 2017)

mikestony said:


> So there are 3 temp sensors correct? One in the thermostat housing, one in the water outlet, and one on the lower side of the radiator?


So far I have found a sensor in the lower radiator hose and another in the water outlet on the side of the head. If there is a sensor in the side of the radiator, I hope someone will speak up. My car is a 2014, not sure if earlier models are different.


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## mikestony (Jan 17, 2013)

Jon87transam said:


> So far I have found a sensor in the lower radiator hose and another in the water outlet on the side of the head. If there is a sensor in the side of the radiator, I hope someone will speak up. My car is a 2014, not sure if earlier models are different.


1.4 liter turbo? 
I'll have to check your year/make/model a sec.

But my temp sensor in the radiator is just above the drain on the right lower side of it. Mine's a 2012 1.4L turbo.


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## mikestony (Jan 17, 2013)

Jon87transam said:


> So far I have found a sensor in the lower radiator hose and another in the water outlet on the side of the head. If there is a sensor in the side of the radiator, I hope someone will speak up. My car is a 2014, not sure if earlier models are different.


Also, a little confused by your temp sensor in the lower radiator hose? 
Not seeing one on Alldata...just the thermostat housing temp sensor, the water outlet temp sensor and the radiator one:


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## Gr3mlin (Jul 6, 2021)

Would love an update here!


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## Cruze CTRL (Sep 16, 2021)

Gr3mlin said:


> Would love an update here!


A ~good thread Otherwise.. Elvis has just left the building.


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## [email protected] (Feb 6, 2018)

My 2014 Cruze just last night threw the message a/c off due to cold temp. Under the hood everything was fine. Interested in more info.


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## Blasirl (Mar 31, 2015)

[email protected] said:


> My 2014 Cruze just last night threw the message a/c off due to cold temp. Under the hood everything was fine. Interested in more info.


Welcome ahhh Back!

While I cannot read the verbal vomit the OP posted, I at least get your question.

Make sure you have properly "burped" the system. This is a brief How-To care of Dhpnet:

Fill Procedure:
1- close the radiator drain plug.
2- lower the vehicle
3- vehicle should be level
4- Loosen the vent screw on the radiator

(vent screw is located at the top, right (passenger) side of the radiator)

NOTE: Close vent screw when coolant begins to flow from the vent screw.

5- Add a mixture of 50/50 DEX-COOL antifreeze and clean drinkable water to the bottom line of the bleed nozzle on the coolant surge tank. When the coolant level stabilizes, add enough coolant to reach the bottom line of the down pipe hole.
6- Start the engine. After the engine starts, verify that the coolant level reaches the bottom line of the down pipe hole.
7- Install the surge tank cap
8- warm up the engine. Run at 2,500 RPM until the engine cooling fan turns ON.

Note: If the heater core has been replaced, let the engine run for 2 minutes at 2,000-2,500 RPM. This ensures complete venting of the cooling system.

9- Turn the engine OFF and allow the engine to cool down.
10- Remove the surge tank cap.
11- Check the coolant level and fill to the COLD mark if necessary.
12- Inspect the concentration of the engine coolant, using GE-26568 tester.
13- Rinse away any excess coolant from the engine and engine compartment.

NOTE: After a test drive let the engine cool down and check the coolant level again. Adjust the coolant level to the COLD mark if necessary.






If it still is giving issues it is time to check the sensors.

AC off Due to high engine temp links
Troubleshooting temp sensors

more info here:








2012 1.8L Cruze - Loud Fan Noise


I got an issue with my cruze. The fan lets off a jet-like sound ALL THE TIME meaning it will stop only if I turn off the car. The heating works great and I am currently using the heating due to the weather (Below zero temp/snow in Quebec, Canada). One thing I noticed, on a cold start, the car...




www.cruzetalk.com


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## Kristol (Feb 22, 2020)

I have a 2014 cruze 1.4 2lt with a temp sensor in the thermostat hose lower end close to radiator. No sensor on radiator.


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