problems with coolant
 

I noticed about 2 weeks ago my low collant light came on my 2005 duramax. I looked at the overflow and it had coolant in it but the tank was green. I cleaned out the overflow and topped collant off and thought problem was fixed. Now 2 weeks later I pulled truck out and it was ideling for about 5 min. then noticed large puddle of antifreeze on the ground.

I changed radiator cap and both thrmostats, but it continues to rise into overflow when ideling or warming up. once thermostasts open up fluid drops and notice small amount of bubbles in overflow tank. upper radiator hose is swollen and hard. Does anyone have any ideas EGR vs HG?? Please help truck only has 84 thousand miles. One month out of warranty.