Overheating warning/engine cooling issues.
 

I noticed something very strange while driving my Chevy Equinox '06. Yesterday I went to the car wash and during the wash my coolant warning came on. Initially I thought it was just bec of the carwash (like hot water or something). Shortly after leaving the car wash the temperature went down to it's normal levels. I stopped thinking about it up until today. I drove it today and the temperature seemed little bit higher that usual from 45% to 75% ( 50% is what I call the middle of the gauge - 100% is already overheated critical issue). So with that 45-75% in mind I started thinking about the issue again.

When I came back home I allowed the car to idle for about 3 minutes. The overheating warning came on. I switched the car off and it kept cooling itself for about 10-15 minutes ( fan under the hood kept going so this is how I know it).
I came back to see how everything looked. Seems it cooled itself down to 50%.

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An update: After the check up my mechanic found out that my head gasket was broken. It's now replaced and the car is well, but I'm noticing that my coolant level is dropping slowly... I will need to ask my mechanic for additional help.

My 05 has cracked head similar symptoms with heat.