What causes the temperature gauge in a 97 ford expedition to move to hot and turn on the oil light?

Answer 1

This is obviously caused by an overheat situation. The 4.6 and 5.4L engines have an engine "failsafe" system which will make the vehicle run on 4 cylinders and alternate the remaining four to serve as air pumps to assist in cooling the engine at a reduced performence. The air conditioner will not work and the lights you mentioned will come on. If your vehicle is run under these conditions for a long time, you can cause major damage to the cylinder head gasket and may cause warping to heads. You will know this accured if you notice a white milky residue on the oil dip stick or notice oil in the radiator reseviour. there are other indicators though like excessive water comming from the exhaust or an antifreeze smell coming from the tail-pipe. another is that you will have decreased performance rough running and loss of compression in the cylinders. Please take this vehicle to a qualified mechanic before you cause more extensive damage to it. Please don't go strictly by finding a small amount of this residue on the oil cap. sometimes the humidity in the engine will cause this on the cap itself and should not really be used as an overheat indicator..