I purchased by 2012 Dodge Avenger brand new and have no had any issues. The temperature gauge has always ran right below the half way mark (white line) but recently is going a tad over and running around the half way mark. It hasn't gone any higher and I know the half way mark doesn't concern many but should I have the thermostat checked to make sure it's working properly. I live in Georgia and before long will have those very hot days and want to make sure this doesn't become an issue.
If you're having doubts about your cooling system, I would bring it in to have it serviced. I would recommend a coolant system flush and replenish with a fresh 50/50 mix. If you're a "do it your selfer", they sell flush kits at your local auto parts store. And yes, for the cost of a thermostat, have it replaced.
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