It is the two wire sensor next to the thermostat housing.
What type of coolant sensor? The below answer is for the coolant LEVEL sensor. The coolant TEMPERATURE sensor on my vehicle is located just next to the thermostat housing. On the front top center area of the engine just behind the radiator. Follow the coolant hoses if you have trouble. On my 1995 Jeep Grand Cherokee the sensor is located on the top of the plastic coolant reservoir tank. Look for a small (2-wire?) electrical connector.
On the coolant overflow bottle that in on the passenger side of the engine.
Under hood, center, upper engine area, mounted in driver side of water outlet
The coolant temperature sensor on a 2001 Jeep Cherokee is located in the intake manifold. It monitors the flow and temperature of coolant through the engine.
located coolant temp sensor
The engine coolant temperature sensor is the sensor that is screwed into the thermostat housing on the top front of the engine.
Low coolant or bad sensor
sensor is located on coolant housing at engine front
The 1995 Chevy Silverado coolant sensor is located on the front of the engine. The coolant sensor will be a few inches above the thermostat housing.
There are two, and they are located on the side of the block and the other is in the coolant tank. Both are under $30 each at Schuck's/Checker's/Kragen/O' Reilly's.
The coolant temp sensor is located next the the thermostat housing.
The 2006 Honda Civic coolant temperature sensor is located on the front of the engine. The coolant temperature sensor will be in the vicinity of the thermostat housing.