It's located in the engine block, usually near the thermostat housing. It's a single-wire sensor that screws into the engine. However, its exact location can vary slightly depending on the specific engine casting.
To be certain, you should:
1. Consult a repair manual: A Haynes or Chilton repair manual specific to your 1995 Chevy Monte Carlo 3.1L will have a diagram showing the exact location of the ECT sensor. This is the most reliable method.
2. Look for a single-wire sensor near the thermostat housing: Start by visually inspecting the area around the thermostat housing. Look for a sensor that's about the size of your fingertip, with a single wire connected to it.
3. Use a temperature gun: While not pinpointing the location exactly, a temperature gun can help identify the area of the engine block that's responsible for initiating the fan operation.
Remember to disconnect the battery negative terminal before attempting any work near the cooling system to prevent accidental short circuits.
