Coolant Temperature Sensor — Checking and Replacing (Opel Zafira A)

The necessity of performing this operation should be determined during the inspection of the technical condition of the engine control system (see "Engine management system - technical condition check and fault diagnostics").

To complete the work you will need a multimeter and a thermometer.

Warning! Before performing the operation, be sure to read the section "Safety precautions for maintenance and repair of the engine management system".

Examination

Checking the coolant temperature sensor involves measuring its resistance at different temperatures and comparing them with reference values (are given in the table). To check, remove the sensor (see below), connect a multimeter to it in ohmmeter mode and lower the thermoelement into a glass of hot water. Also lower a thermometer into the glass. As the water cools, record the ohmmeter readings at the temperatures given in the table. If the obtained values differ from those given, replace the sensor.

Table 9.2.3. Coolant sensor resistance depending on temperature

Replacing the sensor on 1.4 and 1.6 DOHC engines

1. Prepare the car for work (see "Preparing the car for maintenance and repair").

2. Disconnect the wiring harness connector from the sensor.



3. Using a 19 mm socket wrench, loosen the sensor.



4. Unscrew the sensor from the cylinder head and remove it.



5. Install the sensor in reverse order.

Replacing the sensor on a 1.8 DOHC engine

(Material copied from this portal: OpelBook.ru)

1. Prepare the car for work (see "Preparing the car for maintenance and repair").

2. For convenience, remove the decorative engine cover (see "Engine trim panel - removal and installation").

3. Disconnect the wiring harness block from the sensor located in the thermostat housing.



4. Using a 21 mm socket wrench, loosen the sensor.



5. Unscrew the sensor from the cylinder head and remove it.



6. Install the sensor in reverse order.