I had this problem with a Toyota some time ago with high mileage. Would start to overheat on highway, especially when climbing hills. To get it to cool down, I just had to stop and let the car idle, and it would cool down again. Turned out to be a 75% blocked radiator - flushing did no good - they had to rod it out, and that finally fixed it.
The infamous "coolant gunk" problem reported in this forum affected 3.5 as well as 6.1 liter engine Chargers. Did your car have this problem, and if so, did you have the issue addressed/fixed? If not, that might be contributing, and you may need a better flushing out of your cooling system.
A leak at the water pump usually means your water pump is bad or getting ready to go bad. Might want to have that addressed sooner rather than later.
2006 Black Charger SRT8 Loaded
2007 Mini Cooper S Loaded
Favorite Quote from Team SRT:
"The 5.7l engine was designed to be a balance of cost weight and power.
The SRT 6.1L engine was designed to kick ass."
Last edited by ortizmro; 01-29-2008 at 12:37 PM.