How to Locate the Engine Coolant Temperature Sensor on a 1995 Isuzu Trooper

The Isuzu Trooper came to the U.S. in the 1983 model year, as a not-so-pretty vehicle, but off-road enthusiasts loved its off-road capabilities. The Trooper lived a long life, despite its appearance, as Isuzu kept it around through the 2002 model year. The 1995 Trooper had two 3.2-liter engines available: The standard engine was a SOHC version that produced 175 horsepower, and the optional version was a 190-horsepower DOHC engine. The engine coolant temperature sensor read the temperature of the coolant and relayed the information to the vehicle's computer and the temperature gauge on the dashboard. Replacing this sensor is a straightforward task, but you need to bleed the cooling system afterward.

Instructions

Locating and Replacing the Sensor

1

Look on the rear of the Troopers engine and find the electrical component screwed into the right side of the engine block on DOHC models, or the left side on SOHC models. This component is the engine coolant temperature sensor.

2

Slide a drain pan under the ECT sensor to catch any coolant that may leak out.

3

Pull up on the locking tab on the ECT sensors wiring harness and pull the wiring harness from the sensor.

4

Remove the sensor by unscrewing it with a ratchet and deep-well socket.

5

Apply a thin coat of thread sealer to the threads on the new ECT sensor and allow the sealer to dry for the time specified by the sealers instructions -- typically 5 to 10 minutes.

6

Hand-tighten the ECT sensor into the rear of the engine block. Tighten the sensor to 15 foot-pounds with a torque wrench and deep-well socket. Plug the wiring harness into the receptacle on the ECT sensor.

Refilling and Bleeding the Cooling System

7

Unscrew the cap from the radiator and add 50-50 premixed ethylene-glycol-based (green) coolant to the radiator until the level reaches the base of the radiator filler neck.

8

Pull the cap on the cooling system reservoir upward to open the reservoir and add 50-50 premixed ethylene-glycol-based (green) coolant to the reservoir until the level reaches the Max line.

9

Start the Troopers engine and hold the vehicles rpm from 2,500 to 3,000 until the temperature gauge on the instrument cluster reaches about halfway.

10

Hold the rpm for an additional five minutes, then allow the SUV to idle. Check the level in the radiator and add coolant, as needed, to raise the level back to the base of the filler neck. Repeat this step until the coolant level in the radiator remains steady. Tighten the radiator cap onto the radiators filler neck.

11

Shut the engine off and allow it to set until the engine is cool to the touch. Add 50-50 premixed ethylene-glycol-based (green) coolant to the cooling system reservoir until its level reaches the Max line, if needed. Close the cooling system reservoir cap.

12

Take any old coolant in the drain pan to a used automotive fluid-recycling center. Some auto parts stores take used coolant free of charge.