oldsmobile sihlouette running hot

Could be t-stat, low coolant, fans, head cracked, head gaskets, water pump, have system pressure tested for leaks, and chemically tested for combustion gases in coolant.

Blown head gasket cracked head or block inop fan or coolant temp sensor not turning the fan on at the correct temp.Clogged radiator tubes or radiator fins so the air cant be pulled thru.Bad thermostat without testing its hard not possible to figure it out or it could be something i just didnt think of off the top of my head.