# 2012 Cruze boiling coolant in reservoir.



## fyrftr422 (Aug 15, 2012)

I've had the typical coolant issues with this car from the beginning (bought new in June 2012, now has 310k) but they have reared their ugly head again. 

We're finding we have coolant boiling in the reservoir now, and at times have even heard it boiling in the top of the engine (My Wife has video, now I just need to figure out how to post it). The kicker, it isn't happening every time we drive and I only lose a bit of coolant each time and only once has the car ever overheated (due to loosing coolent over a few days and not being diligent topping it off), otherwise the coolant temp never wavers from the norm. 

My mechanic cannot replicate this even idling for a couple hours and is stumped. We replaced the thermostat and I have considered changing out the reservoir (I have the original with the escape tube taped/tared) as I may have a pressure issue. I've read a few thread son here about the cooling issues a lot of us have had but haven't come across a boiling reservoir that isn't showing an overheating engine.

Hoping someone else has experienced something similar.


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## obermd (Mar 3, 2012)

What's the thermostat display read when you see/hear the coolant boiling?


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## fyrftr422 (Aug 15, 2012)

Only once did it shoot into the red, when it overheated, every other time it never moves from our standard operating temp, just under the halfway mark (not sure what temp that indicates).


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## fyrftr422 (Aug 15, 2012)

Oh, and replacing the thermostat changed nothing. The car was boiling in the reseervoir when I got it home after the change.


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## obermd (Mar 3, 2012)

fyrftr422 said:


> Only once did it shoot into the red, when it overheated, every other time it never moves from our standard operating temp, just under the halfway mark (not sure what temp that indicates).


Depending on when in the 2012 production run your car was made one of the DIC displays will give you a digital readout of the temperature (earlier models had this). The needle sitting steady just means the car is operating between 180 and 220F.


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## fyrftr422 (Aug 15, 2012)

I never even thought to go through the digital readings for a temp (I'm sure my car has this), I just assumed as long as my needle wasn't moving much, I never needed to know the actual temp as it was AOK. What is an operating temp I should be looking for?


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## obermd (Mar 3, 2012)

fyrftr422 said:


> I never even thought to go through the digital readings for a temp (I'm sure my car has this), I just assumed as long as my needle wasn't moving much, I never needed to know the actual temp as it was AOK. What is an operating temp I should be looking for?


180 to 220F is the normal operating temperature range for all Gen 1 1.4T Cruzen (LT, ECO, LTZ). If you're in this range, and I suspect you are, and you're getting boiling coolant then the pressure cap on the surge reservoir isn't holding pressure.


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## ChevyGuy (Dec 13, 2014)

obermd said:


> isn't holding pressure.


That's my vote. There's something preventing the system from building pressure. Without pressure, the coolant WILL boil, even at normal operating temperature.


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## fyrftr422 (Aug 15, 2012)

After reading other threads on this, that was my primary thought as well. Did I read correctly that GM redesigned the reservoir or would it be better to go with the Dorman part I've seen in a couple threads, along with a new cap, or gasket at least?


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## plano-doug (Jul 1, 2015)

fyrftr422 said:


> After reading other threads on this, that was my primary thought as well. Did I read correctly that GM redesigned the reservoir or would it be better to go with the Dorman part I've seen in a couple threads, along with a new cap, or gasket at least?


I think I gave 35-40 bucks at the dealer parts counter for the coolant tank for my 2012 Cruze. I don't have any experience with the Dorman tank. Knowing how Dorman can be hit-or-miss, I'd get the OE tank. Make sure you get a new cap to go with.

Doug

.


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## CRUISE-CRUZE (Nov 8, 2010)

Read my post:
https://www.cruzetalk.com/forum/34-gen1-1-4l-turbo/225041-1-4-eco-thermostat-swap-221-f-176-f.html


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## obermd (Mar 3, 2012)

Unless you can see a specific issue with the reservior, it's probably fine. I had a consistent leak/seap out my pressure cap. When the car is cold, take the pressure cap off the tank and look between the two o-rings. If you see coolant there the problem is your cap needs a new lower (when on the tank) o-ring. Take a look at https://www.cruzetalk.com/forum/25-...fix-coolant-odors-coolant-loss-reservoir.html for more information on the coolant tank and pressure cap.


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## fyrftr422 (Aug 15, 2012)

The tar/tape job done by GM on the reservior is starting to show steam when it boils over which tells me that there might be a problem with that connection, hence my thoughts on just replacing the tank altogether. I'll definitely check my cap next drive though and see if there is evidence of coolant between the rings.


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## obermd (Mar 3, 2012)

fyrftr422 said:


> The tar/tape job done by GM on the reservior is starting to show steam when it boils over which tells me that there might be a problem with that connection, hence my thoughts on just replacing the tank altogether. I'll definitely check my cap next drive though and see if there is evidence of coolant between the rings.


You can safely pull that monstrosity tar/tape job off and not impact the integrity of the tank.


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## fyrftr422 (Aug 15, 2012)

Still baffles me that that was their fix, under warranty, no less. Ugly fix for sure, but I guess I can't complain, it did last for at least 200K.


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## fyrftr422 (Aug 15, 2012)

obermd said:


> Unless you can see a specific issue with the reservior, it's probably fine. I had a consistent leak/seap out my pressure cap. When the car is cold, take the pressure cap off the tank and look between the two o-rings. If you see coolant there the problem is your cap needs a new lower (when on the tank) o-ring. Take a look at https://www.cruzetalk.com/forum/25-...fix-coolant-odors-coolant-loss-reservoir.html for more information on the coolant tank and pressure cap.


It was Blue Angel's original post, that you added to your thread, that gave me the impression I was dealing with a pressure situation. Both very comprehensive and informative threads, Thanks !!!


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## obermd (Mar 3, 2012)

@fyrftr422,

The o-ring that solved my ECO's coolant loss was a 4.5mm X 23mm (NBR) Buna-N 70 Duro Metric O-Ring (4.5mm X 23mm (NBR) Buna-N 70 Duro Metric O-Ring [N4.50X023] : The O-Ring Store, We make getting O-Rings easy!)


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## fyrftr422 (Aug 15, 2012)

5 for about $4 Can, but around $20 Can to ship, ouch! cheap fix I suppose.


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## fyrftr422 (Aug 15, 2012)

obermd … You mentioned it does not like the cold much and thought it might not hold pressure in wonter. I didn't see a further post about it. Have you found that to be the case. Pretty cold up here in the Great White North, these days.


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## obermd (Mar 3, 2012)

fyrftr422 said:


> obermd … You mentioned it does not like the cold much and thought it might not hold pressure in wonter. I didn't see a further post about it. Have you found that to be the case. Pretty cold up here in the Great White North, these days.


This o-ring seeps until it gets to about 70F. Above that it holds pressure like a champ. I would lose about one to two inches of coolant over the winter - call it the perpetual coolant drain & flush.


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## fyrftr422 (Aug 15, 2012)

Thanks for the info !!!!


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## Kbolecho1 (Aug 30, 2018)

*Coolant reservoir leak*

Today my daughters 2012. Cruze had very little coolant in the reservoir. Not sure where it is leaking from or where the coolant went . I went a head and changed the cap out and removed the unit and checked for cracks underneath. This is the second time I have filled the case.


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## CRUISE-CRUZE (Nov 8, 2010)

If you will read my post you will learn that the gauge we have is *useless*, you will boil the coolant without even knowing it! Then the original thermostat is opening "too high" so if you have air into the system or your system is not very well pressurized then you will boil the coolant to a much lower temperature. I did a lot of tests on a few Eco and replacing the thermostat was the best solution. These days are -5F in my area and had no issues with the heater, and during the summer also no more boiling coolant due to the new thermostat. I did the change for a few other cars and none of my friends had issues anymore. If you argue about the thermostat is opening "too low" and "performances" then let me tell you that I didn't see any major change on MPG..


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## fyrftr422 (Aug 15, 2012)

Well, I have a new reservoir tank and cap arriving within a few days, with the beefier O-rings. This should solve my pressure issue (assuming that is what is happening) so we'll see if the new thermostat does the trick. It already boiled with it, but hopefully, with the pressure situation solved, should be good but replacing the thermostat alone, was not the solution.


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## obermd (Mar 3, 2012)

fyrftr422 said:


> Well, I have a new reservoir tank and cap arriving within a few days, with the beefier O-rings. This should solve my pressure issue (assuming that is what is happening) so we'll see if the new thermostat does the trick. It already boiled with it, but hopefully, with the pressure situation solved, should be good but replacing the thermostat alone, was not the solution.


Get some coolant dye and put it in once you're done with the swap out. This dye leaves a visible residue near any leaks.


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## fyrftr422 (Aug 15, 2012)

Good call, I've heard others were given it by their local GM dealership.


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## obermd (Mar 3, 2012)

fyrftr422 said:


> Good call, I've heard others were given it by their local GM dealership.


I got mine free but it was while my Cruze was under the B2B warranty. Even if it's not free, a bottle is only $10-15 so it's well worth it to track down leaks.


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