So you put the "Guts" of the new Dorman thermostat in the original Cruze housing?

Both the Cruze and the Volt share the same 1.4L engine. The Volt not having the turbo. Are the gaskets and mount holes not the same between the two thermostats?

Why couldn't you just use the Dorman thermostat as is?

I agree that as these cars get older leaks are going to be bigger issues.

 

The housing and seal has a different outside shape, otherwise I would just replace the entire unit.

 

I think you should have spent more time identifying the root cause of your other problems. In my ownership of the Cruze I haven't had to replace those components and haven't had to top off any antifreeze.

I don't think what you did was a good idea. The engine needs to run hot enough for efficiency and without a re-tune, you might see a drop in fuel economy. Furthermore, engine oil needs to operate above the boiling point of water to prevent condensation and water contamination from building up. That point is 212F. You running the thermostat below that temperature means you'll likely also need to change oil more often since oil will not reach above the boiling point of water, which may cause it to break down more quickly.

A 195F thermostat may have been more appropriate.

 

I don't think what you did was a good idea. The engine needs to run hot enough for efficiency and without a re-tune, you might see a drop in fuel economy. Furthermore, engine oil needs to operate above the boiling point of water to prevent condensation and water contamination from building up. That point is 212F. You running the thermostat below that temperature means you'll likely also need to change oil more often since oil will not reach above the boiling point of water, which may cause it to break down more quickly.

A 195F thermostat may have been more appropriate.

This is interesting. My daughter has a 2015 1.6T and the engine runs around 105C. I have a 2012 diesel and it runs around 80-85C summer or winter. Both our cars have the digital temperature displays and the diesel gauge starts to move at 50C, not sure about the daughter's car as I don't drive it much. The heater starts working before the gauge starts moving.

 

That's why the day my water pump broke, the engine's fan was going full throttle, while the temp gauge stayed in the center, not moving an inch.
The engine was basically running dry on coolant. I could swear it would be coitus-ing up my car!

 

Idk what you guys are talking about, my cruzes tamp gauge went all the way up to the red when my water pump decided to kill itself

 

I can confirm using my ultra-gauge that the temp gauge is completely useless, and as OP mentioned, it reaches one tick below half at 185F and does not move from 185-226. The car during initial warm up will reach as high as 226.4F before opening the thermostat and settling back down between 208F and 221F. If I remember correctly, there are only two other places the temp gauge will touch over the "one tick below half normal operating point" It will go to 3/4 when the computer senses an overheating condition. This will also trigger the A/C Off due to high temp alarm on the DIC. The other is it will reach 100% hot when the computer senses a severe catastrophic failure such as a "no coolant" condition.

I also agree messing with the thermostat operations as designed may have unintended negative consequences, and I can't recommend that anyone else on here follows this advice, though I find it very interesting.

 

My 12 LT has the original Trifecta select-a-tune. With the tune the digital temp, not the gauge reads 199-203 coolant temps. It remains the same in both eco mode and sport mode. Been 80k miles plus and no ill effect with mine.

 

Conclusion!

Let me share with you the observations after I did this Thermostat Swap to 4 cars, all have at least 5K since the change:

• During cold weather the coolant stays most of the time around 184F ±2F. Some exceptions if you are stuck in traffic when the coolant’s temperature goes higher since the “smart” ECM won’t start the fan so early.
• When is hot outside, over 100F, the thermostat works great, your coolant stays again around 184F most of the time! It is even better than in the cold weather because this time you are using AC and the radiator’s fan works very often, getting down the temperature. No issue if you are stuck in traffic, I never got the temperature over 190-192F and that only for a few seconds!

All 4 cars I changed behaved in similar way, I only had same issue with one in particular, until I did a better air flush to the coolant.
To summarize: I got the engine working temperature down from 221++F to ~184F, in order to avoid continuous overheating issue (the gauge is useless, it goes max to 185F, so you can boil the coolant without even know!). I didn’t see any MPG major fluctuation after the change. I never had issues with car warming up during the cold weather, nor overheating during the hot days and rush hours. I’m not going to argue about better engine performance at higher temperature, but this is not a racing car!

Ideally.... ideally I'll do the swap to a thermostat that would open at 195F-200F but the only one that fits and I could find is the one I mentioned into the original post. I didn't want to change the housing, add adapters, etc. If somebody can find a better thermostat, let us know!

 

Let me share with you the observations after I did this Thermostat Swap to 4 cars, all have at least 5K since the change:

• During cold weather the coolant stays most of the time around 184F ±2F. Some exceptions if you are stuck in traffic when the coolant’s temperature goes higher since the “smart” ECM won’t start the fan so early.
• When is hot outside, over 100F, the thermostat works great, your coolant stays again around 184F most of the time! It is even better than in the cold weather because this time you are using AC and the radiator’s fan works very often, getting down the temperature. No issue if you are stuck in traffic, I never got the temperature over 190-192F and that only for a few seconds!

All 4 cars I changed behaved in similar way, I only had same issue with one in particular, until I did a better air flush to the coolant.
To summarize: I got the engine working temperature down from 221++F to ~184F, in order to avoid continuous overheating issue (the gauge is useless, it goes max to 185F, so you can boil the coolant without even know!). I didn’t see any MPG major fluctuation after the change. I never had issues with car warming up during the cold weather, nor overheating during the hot days and rush hours. I’m not going to argue about better engine performance at higher temperature, but this is not a racing car!

Ideally.... ideally I'll do the swap to a thermostat that would open at 195F-200F but the only one that fits and I could find is the one I mentioned into the original post. I didn't want to change the housing, add adapters, etc. If somebody can find a better thermostat, let us know!

Question: What impact has running cooler had on your emissions? Part of the reason the Cruze runs so hot is for emissions purposes - hotter engines tend to burn cleaner.

 

A friend had a Mini (original1966) and had 2 temperature gauges fitted. One for water and the other for oil. The water ran at 180F and the oil went to 250F, even though he had an oil cooler. I know the diff and transmission are in the sump, but the oil still runs hotter than the coolant in most cars that I have owned.

 

I am really like the idea of a lower temp thermastat. I've always worried more about overheating than condensation in the oil. My old 86' pickup got a 160° F thermastat in it. Now I understand that theses engines are better off closer to 220° and that's fine...givin that the gauge would show it! As y'all have said the gauge goes to a tick below halfway and stops. That is the reason I had to put another engine in my 2011. The fan resistor, on the fan shroud, burn up or messed up from corrosion , causing the fan to only run on "turbo" mode when the a/c high side got to high. Before the engine swap I replaced the head gasket, thinking that was my problem, and when I got it back together I used my ODBll scan tool to monitor the temperature, which goes off the outgoing sensor on the rear of the engine, and saw temps up to 250°f , no fan and the temp gauge on the dash still never got above the tick below halfway. That tells me whoever had the car before me along with myself had been running it hot for a long time and never knew it and cooked the engine. Having an old school thermastat at a slightly lower opening temp would make me feel a lot better.

 

1st, thank you CRUISE-CRUZE for the research and time it took to find the parts to do this!
i have done this and am VERY happy with the results. my car is now running at 185° ± 5°. Most of the time i run 180° but when climbing a steep grade on my daily commute the temp does raise to 190°. i have noticed if i let the car sit and idle for an extended period of time (30-40 minutes) the temp will climb to 210°.
the last few weeks the temp has been in the high 20s to low 30s F i have had no problem with the heat in the vehicle.
After my commute to work, the coolant temp is always about 180° and i have taken several temp reading of the cams and the temp of the cams was 218°F. i do not have a way to measure the oil temp but an infrared thermometer aimed at the cams under the oil fill cap is good enough for me. this temp of the cams mitigates the thought that the oil will not get hot enough to evaporate moisture.
my MPG has not changed at all

i ordered the following from rockauto

MOTORAD T46 - CAP
DORMAN 9022080 - Thermostat
DORMAN 603383 - Coolant recovery tank

why isnt this a sticky?

 

Thank you for your post! A few other people asked me and it is good to know when somebody else does changes that are working and help us to deal with our issues. I counted 9 cars, including you, that I'm aware about this change (or I did it myself to a few) and have no more issues. Two main things to watch:

1. The thermostat has 2 version, one version you can't take out the inside component so you need the other one, see it also here:
https://www.ebay.com/itm/112394548622?ViewItem=&item=112394548622&ppid=PPX0

2. Make sure you properly add back the coolant after the replacement and take out the air from the installation when done!

As a remark, the latest Cruze model (1.4 turbo) is using the OE thermostat that opens at 82 Celsius! You can't use that model, it doesn't match to our 2011 & 2012 models but just for your reference only, the thermostat that opens at 105C "to improve car performances" is for a different application, market, in my opinion.

 

The summer here it gets into the high 90s to low 100s. I have always put lower temp thermostats in my vehicles for this reason. Thanks to Cruise Cruze I can now run a cooler thermostat in my Cruze too

Doing this isn't for everyone. Either is the big brake mod or the PCV mod or the CDV mod.

This information is valuable to those who would like to do this

Sticky this



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Question: What would be the effect of just changing the cap to 15lbs? That 25% reduction in system pressure seems where most of the benefit comes from. As far as I can tell, the boiling point would be 267F down from 282F. (This is for generic 50% antifreeze - I couldn't find a table for Dexcool.)

Edit: For Dexcool, it's 260F/266F/277F depending on 40%/50%/70% mixture at 15lbs. I don't know what it is for 20lbs.

What hasn't been addressed is the temperature gauge that doesn't give good warnings. That's going to take a computer solution.

 

In theory, yes, it is better to have a higher pressure into the system. But in reality the extra pressure damages the hoses, connections, expansion tank, etc. See how many issues are related with that on this forum. Look around to other similar cars and see the cap spec. I monitored long enough the system and the active grille shutter has also influence on controlling the coolant temperature. Not efficient at all under different circumstances, when for example the grille it is locked into a random positions due to the outside temperature. That is another story, they dropped also this extra feature that was very advertised when they came in US with the first Cruze generation. I have mercury tilt switch on the grille connected to an LED inside the car so during the years I could daily monitor its behavior. The thermostat for the first Gen is also "smart" so the computer supposed to properly control the temperature and open/close the thermostat and grille based on different algorithms. The intention was good but not efficient in my opinion....

 

modifying the thermostat without adapting the software tune will cause trouble codes... the ECM controls the thermostat to a desired ECT and will set a DTC and MIL if it does not see that temperature after a certain time

 

None yet with mine.

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i had an oil analysis done on my last oil change.

 

Hotter engines produce more NOx.

I'd like to know how you all get 250 degree oil out of 180 degree coolant.

I've yet to see my oil get hotter then water.
In fact. I've yet to see it come close to water.

Even my semi don't get hotter oil climbing the mountains. Fan kicks on at 215. Hottest I've seen oil is 210. And it all cools right back down on the down hill side.

 

Hotter engines produce more NOx.

I'd like to know how you all get 250 degree oil out of 180 degree coolant.

I've yet to see my oil get hotter then water.
In fact. I've yet to see it come close to water.

Even my semi don't get hotter oil climbing the mountains. Fan kicks on at 215. Hottest I've seen oil is 210. And it all cools right back down on the down hill side.

Idk, but my oil temp is always higher than coolant temp after some driving. Not sure where the sensor is but oil temp 230-240. Coolant temp in the 220s.

2 different days. First one in park.. 2nd one idle in drive.

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Unless you have an oil temperature gauge, what are you basing your oil temperature on? Unless things have changed it has been my belief that oil temperature is not influenced very much by normal engine temperature. After all there is an oil cooler in the radiator for the transmission. Doesn't that then indicate the the oil is hotter than the coolant?

 

OIl gets it's heat from the engine. How can you make it hotter then the engine? Water heats up faster then oil.

Car has obd. Semi has gauge.

Not only do you have a cooler. You also have air flow around the pan.

 

Oil gets its heat from friction. Any engine temp gauge will show either water or oil temp. Oil temp can vary greatly depending on where the sensor is placed, after oil cooler or immediately after heat source which is bearings, piston rings, etc.

 

Which is hotter. Oil or water? 30 minute commute to work.

 

:tempted:Guys, relax!
I did the change only because I was frustrated like many others to boil the coolant without knowing, I explained also that the gauge temp is useless! I would use a thermostat that would close around 90-95C but there were no options that I could find to replace with minimal changes. And I explained this, even GM change the thermostat later to lower temperature but different housing for the next generation (2017) that opens at... 82C yes! I changed, or help others, to do this change on more than a dozen cars and no issues. I detailed the steps for people who want to improve and avoid issues but don't start arguing now like the Cruze is an F1 car, where every small changes would have a big impact! I keep driving my Cruze/s with this change for that many months, I even forgot about it until I saw this topic opened again. We can debate a lot about it but, unless you have time to put gauges everywhere and go to deep details based on measurements, just look at the real life results: it works! Don't trust it? Don't do it!

 

yesterday was 96 according to the Cruze and AccuWeather reported 94. Cruze ran at 180

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yesterday was 96 according to the Cruze and AccuWeather reported 94. Cruze ran at 180

View attachment 271819

View attachment 271821

View attachment 271823

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Wait, did you somehow convert that dash compartment into a display holder for the radio?!

 

So no impact on fuel economy? Less pressure on hoses and that damned coolant tower I've had to replace twice? Less heat potentially leading to better performance overall? This kinda sound like a win win. I'll be doing this in a few months at the next service...

 

 

One thing many consumers neglect is the cap on the coolant recovery tank. GM uses a 20 PSI cap on the 1.4 liter engine. I just recently replaced the outlet cooling manifold and the upper radiator hose because when the system gets up to normal temperatures coolant was seeping out of the hose at the manifold under pressure. My runnings temps were as high as 240 degrees on hot days running on highways. After I replaced these parts and a new thermostat as well as flushed out and renewed the coolant, temps were marginally lower. Since I've read that the coolant recovery tanks are prone to cracking over time I replaced the tank and cap with a Dorman. Dorman has metal sleeves in the hose fittings for reinforcement under temps and pressures. I pressure tested my old cap on my test bench and found that the original cap bled off at 24.5 psi. Since I live at sea level and in a hot climate I did some calculating on pressures and boiling points so I installed a Dorman 15 psi cap.
This cap actually bled off at 16.5 psi. That is perfect since I was deciding between a 15 or an 18 psi cap. Now my temperatures are running cooler. 215 to 228 degrees Fahrenheit. Right in the range of the rated thermostat of 221 degrees. My point here is replace your cap on your recovery tank. If it fails and starts to hang up the increase pressures might run your temperature up a bit, start pushing coolant out at fittings, but it will stress your plastic fittings, manifold and coolant recovery bottle. It's a cheap fix compared to getting stuck on the road and a tow bill to go with it assuming you didn't damage the engine.

 

CRUISE-CRUZE, thanks for sharing
this cooler Dorman thermostat.
I have a 13 Sonic, and I have modified a couple of conventional thermostats to fit into the 1.4T housing.
I use a resistor to satisfy the PCMs
Looking for voltage/no voltage on the heater circuit.
This dorman is a much better option though.
It also offers potential to have a driver selectable dual temperature capability.
I wired up a switch to the thermostat heater circuit to manually control it while driving. Once the engine stabilizes at ~178°F, I can turn on the heater circuit, and on the highway, the engine temp will drop as low as 156°F at 85° ambient temp. Takes about 40-60 seconds to drop that much.
This could be good for things such as track outings, ect.
And contrary to popular belief, I believe that cooler operating temps could actually be beneficial to fuel economy.
I think that at lower engine temps, detonation is less common, so more timing advance can be used.

My normal operating temps now run between 173-178°F.
If this seems to be a bit lower than typical, it could be because when I was swapping out the "guts", I noticed that the original spring was about 1/8 inch shorter, and seemed to take a bit less pressure to compress, so I kept the original spring.
Now wether this spring is deliberately calibrated differently, just a manufacturing variance, or has softened a bit from use, I dont know.

 

CRUISE-CRUZE, thanks for sharing
this cooler Dorman thermostat.
I have a 13 Sonic, and I have modified a couple of conventional thermostats to fit into the 1.4T housing.
I use a resistor to satisfy the PCMs
Looking for voltage/no voltage on the heater circuit.
This dorman is a much better option though.
It also offers potential to have a driver selectable dual temperature capability.
I wired up a switch to the thermostat heater circuit to manually control it while driving. Once the engine stabilizes at ~178°F, I can turn on the heater circuit, and on the highway, the engine temp will drop as low as 156°F at 85° ambient temp. Takes about 40-60 seconds to drop that much.
This could be good for things such as track outings, ect.
And contrary to popular belief, I believe that cooler operating temps could actually be beneficial to fuel economy.
I think that at lower engine temps, detonation is less common, so more timing advance can be used.

My normal operating temps now run between 173-178°F.
If this seems to be a bit lower than typical, it could be because when I was swapping out the "guts", I noticed that the original spring was about 1/8 inch shorter, and seemed to take a bit less pressure to compress, so I kept the original spring.
Now wether this spring is deliberately calibrated differently, just a manufacturing variance, or has softened a bit from use, I dont know.

Interesting, I like the idea! The only issue is that the temperature gauge is useless (unless they put in Sonic something better?) so you need to watch the temperature to a secondary gauge (OBD) then to act accordingly..
I'm replacing one of my oldest Cruze with a 2014. Same trim: Eco & MT. A lot of downgrades I can see so I'm swapping parts from the old one now. Same issue with the thermostat so I have to swap it again. And it has the PCV issue and the trunk button issue and no light into the glove compartment, etc, etc... I have a lot of re-work to do until fall. I said a few times that owning a Cruze (more) makes me a better mechanic month by month!!

 

I forgot to mention that with the other thermostat I fabricated, i was running around 190°F, and my fuel economy is up from this time last year running the stock 217° thermostat, from about 37 to about 42 mpg.
A good portion of this increase is likely due to improved driving techniques, but I think part of it may be due to the cooler operating temps.