I have a 09 with 5 .7 I don't drive a lot but when I do lately it runs hot if I leave it idle to long it never did this before the antifreeze is not new but does not have many miles on it I was thinking maybe age broke it down ? any ideas ? also can I add something like water wetter into the mopar antifreeze ?

 

Shouldn't need any additives..... Doing a cooling system flush certainly won't hurt, coolant DOES lose some of its properties over time.

What's ambient temp been like lately? Is there an electric fan in there as well? If so, is it still working??

 

its been hot but never had this before it has a fan clutch that is not very old no electric I know I have used water wetter before on older cars so I thought maybe it would help My 17 has no problems staying cool at Idle

 

Your truck have any of the heavy duty packages??

 

towing pack is all I know of

 

That may, or may not... have come with a heavier duty radiator/fan clutch.... When was the last time the system was flushed?