Somewhere I read the coolant is different between 2012 and 2013. I just bought an ex-Hertz Chrylser 200 convertible (nice car) and my coolant tank looks kind of muddy and the fluid color is more opaque than I'm used to. My dealer ran a service history and it shows a thermostat housing replacement was done at some point. Presumably they added some coolant during the service.
What are the consequences if 2012 and 2013 coolants were intermixed? Could the muddy look of the coolant be related to intermixing?