[hatzie]

I have Dexcool in my 2009 Impala, 2005 Silverado, and my 2000 GMC C2500. Never had any problems with any of them.
It's better for aluminum parts and the newer engine gaskets. I've never heard of issues with plastics that were coolant related just the extreme thermal cycling driving out the plasticizers faster and making them brittle.

If you run low on coolant for a good stretch or have combustion leaks into the coolant from head gasket or cracks it's rumored you can have issues with either the green silicate coolants and the various Organic Acid coolant types like Dexcool.

The other way to get into trouble is pouring Silicate coolant into an OAT system. Dexcool doesn't like the green stuff. It gets all kinds of unhappy about being mixed with the old green stuff. That's how the heater cores and engine blocks got sludged up. If you don't know what's in there dump it all, flush it out thoroughly with copious amounts of water, replace the thermostat, and fill with Dexcool 50:50 premix.

I run the green stuff in the older rigs and the manufacturer recommended juice in the new rigs. VW/Porsche/Audi, Honda, and Subaru are especially persnickety about what gets run in them without eating gaskets.