Exhaust gas leaking into cooling system?
 

Moms got a 97 Deville Concours that overheats badly....When I was refilling that surge tank with coolant, with the car running, I noticed that there was exhaust fumes coming out of the surge tank....This is good indication of a blown head gasket...Am i correct? This probably explains why I constantly refill this Northstar with antifreeze....Do you think its a blown head??? Thanks for responding!!!

87,000 miles

If your are losing coolant and and its not leaking on the ground, head gasket is very possible, have proper CO test done to be sure.