I had a 2012 Cruze ECO and now a 2015 ECO. This is a great car and with 42 mpg is very efficient. I had the coolant problem with both cars and have worked with dealers and GM about 3 years and still have the problem. Many customers having the same issues that cannot be resolved in 2011 through 2015 model years.
The sealed coolant system can only lose coolant two ways. 1. By a leak and none have ever been found on my cars and 2. By high temperature allowing gasses to escape out the overflow which appears to be happening. The bulletins and recalls mostly deal with the odor symptom like routing the overflow to the ground and not the root cause of overheating. Obviously they know the tank is venting coolant and by overheating.
It's difficult for customers to know the car is getting a little hot. In fact you have to monitor the OBD11 data to see it overheats because the gauge only goes up to about midway at 190 deg F and even if temperature goes over 240 deg F the gauge does not move further. I have noticed high temperature above 240 deg F in some circumstances that allows boiling, odor and coolant loss. This can happen in the winter and summer both and loss is 4-8 ounces at every oil change.
I looked at the cooling program and it shows a 194 deg mode and a 221 deg mode. The 221 deg mode algorithm does not respond until temperature gets hot in a couple torque modes. The 221 mode is different from the 194 mode and other cars I have looked at. I proposed a program change to prevent this overheat condition and the cause of the odor and fluid loss. Unfortunately I am still waiting on GM to fix the problem, they said if I make the change it will void my warranty.
Please let me know if you have coolant loss/odor and what your thoughts are. I have worked with Dealer, Manager, District Manager, GM Customer Care, Corporate Office and others and still trying to get this fixed and to help them identify the root cause so they can fix this problem for other customers.
This is ECT Program
Here is proposed Program