Engine Cooling problem
2005 Chevy Impala 67,000 miles
Recently we had a lot of work done on my daughter's 2005 Chevy Impala. We had a new radiator installed, hoses, water pump, head gaskets, thermostat, etc. Last night she arrived at my house after driving all day and the temperature gauge had stayed right in the middle where it should be. She parked the car for about fifteen minutes and when she restarted the car, the gauge went all the way over to 260. We opened the hood and the engine was clearly not overheating. When we turned off the car the gauge did not go down to the lowest setting. We let it sit for about 10 minutes and restarted the car. Then the gauge went past 260 into the area of black beyond. WHen we turned off the car, the gauge went back to 260 and was erratic everytime we started the car. The warning sign has never come on to indicate overheating. We are thinking this is a gauge malfunction (a short?) And have learned that it is fairly costly to remove the dash and send it out to be repaired. Maybe we don't have a choice. Any thoughts?
An erratic temperature gauge is normally caused by a faulty engine coolant temperature (ECT) sensor, not the gauges themself. The ECT sensor is what tells teh gauge where the needle should be at. If the sensor fails or the wiring to the sensor fails then it will send wrong signals through the computer system and therefore cause the gauge to read incorrectly. For the 3.4L engines the ECT sensor is located near the coolant outlet on the left rear of engine. For the 3.8L engine it is located below the coolant outlet on the left rear of engine.