2002 Eldorado 56000 miles antifreeze flushed and changed every 2 years. Pull in drive way
coolant gushing out of overflow hose. Heat gauge never rising above middle hash mark no indication of over heating. Any chance of thermostat closing or has all steps taken to avoid the head problem

 

I would start my changing t stat them northstars would good for t stats. They were good for the surge tanks.