How to Install a Coolant Temp Sensor in a 2002 Nissan Truck

As cars and trucks get newer, they get more complicated. It used to be that a mechanical thermostat was enough to keep the engine cool, but now Nissan Trucks come with a coolant temperature sensor that does the job as well. This isn't easy to access, as it's in the back of the engine, next to the firewall. In this case, the project vehicle is a 2002 Nissan Frontier with the 3.3l V6 engine, but the process also works for a 1998-2005 Xterra or Frontier as well.

Instructions

1

Allow the engine to completely cool before working on the cooling system, at least 3-6 hours, but preferably overnight. Place a drain pan underneath the radiator, then open up the petcock on the bottom to drain out all of the coolant from the system. Once the coolant has drained completely, tighten down the petcock.

2

Disconnect the electrical connection to the sensor using your hands. Reach around to the back of the engine and unbolt the coolant temperature sensor from the engine using an open-end wrench. Install the new one in its place using the same method and reconnect the sensor.

3

Open the radiator cap with your hand and fill the radiator with the 50-50 pre-diluted coolant. Then close the radiator cap.