White foam coming out of Radiator fill

[RonV]

I notice white foaming coming from the radiator when I took the cap off!!!! is this something to worry about? Going to flush the system and add antifreeze and see what happens.

[Oz]

STAND BACK!  Your radiator has RABIES!!!

[RonV]

Looks like I will need to put the ole girl down

[Oz]

Caused by combustion gases in the coolant.  Indicates a possible failing head gasket.