2000 Cadillac Coupe DeVille DTS North Star keeps overheating and I don't know why. Replaced water pump, thermostat, misc. gaskets, no detectable leaks. Added internal engine sealer twice. Car consumes 5 quarts of coolant / water after driving for 10 minutes. Not sure where water is evaporating to. Coolant overflow bottle empty after overheating. No issues of overheating during idling, only under load. Please advise.

 

Classic head gasket / head warpage issue. Engine overhaul is required, Cost is about $3,500.