If I recall correctly the thermostat on a 3.5L V6 2000 Oldsmobile Intrigue, is located to the left and below the throttle body. This is located on the drivers side of the engine bay (right side of the engine as you look at it) inside the water neck, which the radiator hose is directly connected to.
the radio was either pulled out or the battery in the car was disconnected at some point you have to go to an Oldsmobile dealer if you do not have the unlock code they will be able to look up off the vin number and walk you through the steps to unlock it
Right in front of the ac condenser. Open the hood look down into the bumper area. There is a plastic air dam small hole with a wire going into it on the passengers side. It is on the back side of that.