# Coolant Boiling



## twclark41 (Sep 6, 2012)

Noticed small amount of coolant on the floor of my garage after having the oil changed. Today I ran home for an errand and noticed a strong coolant smell and vapor coming from under the hood. I opened the hood and coolant was leaking out from somewhere under the resovoir and vigorously boiling in the resovoir. Called the place that did the oil change and in doing so noticed the coolant cap was loose, almost off. Could this loose cap cause the boiling? In driving back to the place that did the oil change I had to stop a few time due to high engine temp. We refilled the with coolant and will see if this loose cap was the problem. My guess is they forgot to tighten the coolant cap down. Would this be the problem?


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## rbtec (Feb 3, 2012)

If the coolant wasn't under pressure it will boil at a lower temperature, just like water boils at a higher temperature in a pressure cooker.


Sent from my Autoguide iPhone app


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## XtremeRevolution (Jan 19, 2012)

It takes about 265 degrees F to boil coolant under 15lb of pressure, at which point your needle would start pegging into the red zone telling you that your car is overheating. Are you sure there weren't just some random air bubbles coming up?

Either way, have your dealer take a look at it.


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## twclark41 (Sep 6, 2012)

Pretty sure most of the coolant either leaked out or boiled off. I suppose what looked like boiling could have been bubbles from somewhere, but what about the steam? I don't think random bubbles would produce the steam. Once the coolant was replaced and the cap tightened it seemed to work fine.


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## XtremeRevolution (Jan 19, 2012)

twclark41 said:


> Pretty sure most of the coolant either leaked out or boiled off. I suppose what looked like boiling could have been bubbles from somewhere, but what about the steam? I don't think random bubbles would produce the steam. Once the coolant was replaced and the cap tightened it seemed to work fine.


Steam can be produced by the coolant falling on other hot surfaces, not necessarily a result of it boiling. Like I said, your engine would have overheated badly before your coolant would have started overheating. 

What engine temperatures was your car showing on the temp needle?

I would also recommend contacting GM customer support to have a case on file with them when you go into the dealership.

Also, was this a 2011 or 2012 Cruze? Was it the 1.8 or 1.4T motor?

Welcome to CruzeTalk by the way.


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## twclark41 (Sep 6, 2012)

It is a 2011 turbocharged 1.4L. The temp was fine on the way home. It is when I shut off the engine and got out is when I noticed the steam and coolant smell. Then when I went to start it up to go back to the service garage is when the problems started. The temp was fine for a couple of miles then it shot up to the high mark on the temp guage and all the warning indicators started going off. I just took it for a 5 mile drive with no problems or apparent leaks of coolant.


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## XtremeRevolution (Jan 19, 2012)

twclark41 said:


> It is a 2011 turbocharged 1.4L. The temp was fine on the way home. It is when I shut off the engine and got out is when I noticed the steam and coolant smell. Then when I went to start it up to go back to the service garage is when the problems started. The temp was fine for a couple of miles then it shot up to the high mark on the temp guage and all the warning indicators started going off. I just took it for a 5 mile drive with no problems or apparent leaks of coolant.


I don't know how the Cruze cooling system is set up as I haven't had a reason to look into it, but on older cars, there was a radiator cap that kept pressure, and when that cap's spring went bad or loosened up, it would cause the coolant to overflow out of the overflow tank. This may be what happened with you, whether that cap is located on the reservoir or on the radiator itself. Should be a simple fix.


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## Big Grouch (Apr 16, 2012)

Yet another reason to not allow minimum wage flunkies to change your oil. I stay away from quick oil change places for reasons like this. The last time I went to one I specifically told them to JUST change the oil, don't touch anything else. Of course they walked in with my air filter telling me how bad it was. It had 3000 miles on it. When I got home I found they didn't latch the filter housing properly, and two of my stainless steel, o ring tire valve caps were missing. Now I either watch for my dealers oil change coupons or just do it myself.


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## twclark41 (Sep 6, 2012)

Big Grouch said:


> Yet another reason to not allow minimum wage flunkies to change your oil. I stay away from quick oil change places for reasons like this. The last time I went to one I specifically told them to JUST change the oil, don't touch anything else. Of course they walked in with my air filter telling me how bad it was. It had 3000 miles on it. When I got home I found they didn't latch the filter housing properly, and two of my stainless steel, o ring tire valve caps were missing. Now I either watch for my dealers oil change coupons or just do it myself.


Yeah, now I'm left with a sticky mess under the hood!


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## GoldenCruze (Dec 18, 2011)

When the coolant gets low it can very well boil, and that boiling can sometimes be seen in the coolant resivoir. Since you drove the car with the engine overheating, even for a short distance, it would be very prudent to change the oil again as soon as possible. The life of motor oil is shortened by heat.


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## mcg75 (Mar 5, 2012)

As the cooling system loses coolant, it will take coolant from the reservoir to replace it. So the coolant loss couldn't have been the reason for overheating if you could see coolant in the reservoir. 

On a hot day, I'm not surprised of leaving the cap loose caused overheating.


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## XtremeRevolution (Jan 19, 2012)

GoldenCruze said:


> When the coolant gets low it can very well boil, and that boiling can sometimes be seen in the coolant resivoir. Since you drove the car with the engine overheating, even for a short distance, it would be very prudent to change the oil again as soon as possible. The life of motor oil is shortened by heat.


I didn't see him mention that the engine overheated...



twclark41 said:


> It is a 2011 turbocharged 1.4L. The temp was fine on the way home. It is when I shut off the engine and got out is when I noticed the steam and coolant smell. Then when I went to start it up to go back to the service garage is when the problems started. The temp was fine for a couple of miles then it shot up to the high mark on the temp guage and all the warning indicators started going off. I just took it for a 5 mile drive with no problems or apparent leaks of coolant.


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## sciphi (Aug 26, 2011)

The system's pressure cap is on the surge tank. An un-tuned Cruze runs about 220*F, which would most definitely boil the water out of the coolant mixture when at sea level. Altitude would make the problem worse. If the pressure cap were loose, simply getting the car up to operating temperature would boil the water out. 

I bet the cooling system has some air in it, and needs to be bled out again. I'd let the car cool down, top off the coolant, turn on the heater to full hot and full fan, loosen the pressure cap, and turn the car on. Dollars to donuts says some air bubbles come out, as that tank appears to be the high point in the system.


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## twclark41 (Sep 6, 2012)

Sounds like my weekend project. Thanks for all the info. No, the engine did not overheat. The gauge simply said High Engine Temp, Idle Engine.


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## mcg75 (Mar 5, 2012)

twclark41 said:


> Sounds like my weekend project. Thanks for all the info. No, the engine did not overheat. The gauge simply said High Engine Temp, Idle Engine.


Overheating means having become too hot. High engine temp, idle engine means the engine has become too hot. 

See the correlation here? LOL. 

Use sciphi method's of check for possible air in the system then test drive the car with the cap on properly. You'll most likely be just fine.


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## Nickerbacher (Jan 17, 2012)

Without pressure the coolant will not circulate back to the block and just flow out of the reservoir overflow tube. Rad cap must be tightly sealed for proper operation of the cooling system.


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## Dale_K (Jul 16, 2011)

The service manual gives a procedure for refilling that starts with opening a vent on the radiator and refilling to the point that coolant is flowing out the vent, then closing the vent and refilling the surge tank to the right level and checking it a second time after the system is completely cold. It does mention something about running it to 2,500 rpm for 2 minutes if the heater core has been replaced.


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## Big Grouch (Apr 16, 2012)

MY 2007 Impala had a very specific way to bleed the cooling system. Not sure about the Cruze, if it were me I'd call the dealer. I once lost some coolant and just refilling it left air in the system, and no heat. Air was trapped in the heater core.


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## mcg75 (Mar 5, 2012)

Dale_K said:


> The service manual gives a procedure for refilling that starts with opening a vent on the radiator and refilling to the point that coolant is flowing out the vent, then closing the vent and refilling the surge tank to the right level and checking it a second time after the system is completely cold. It does mention something about running it to 2,500 rpm for 2 minutes if the heater core has been replaced.


There is a vent screw on the upper passenger side of the radiator.


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## Redford (Oct 10, 2020)

twclark41 said:


> Noticed small amount of coolant on the floor of my garage after having the oil changed. Today I ran home for an errand and noticed a strong coolant smell and vapor coming from under the hood. I opened the hood and coolant was leaking out from somewhere under the resovoir and vigorously boiling in the resovoir. Called the place that did the oil change and in doing so noticed the coolant cap was loose, almost off. Could this loose cap cause the boiling? In driving back to the place that did the oil change I had to stop a few time due to high engine temp. We refilled the with coolant and will see if this loose cap was the problem. My guess is they forgot to tighten the coolant cap down. Would this be the problem?


Top it off with antifreeze and tighten the cap. DONE!


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