The engine is equipped with two coolant temperature sensors. One sensor is located at the rear of the thermostat housing to the left of the cylinder block...
...the second sensor is on the right side in the engine cooling system radiator.
Replacement
The need to perform work is determined during diagnostics of the engine control system. Before replacing the sensor, you should check the condition of its terminals and the condition of the junction block. It is possible that the cause of the malfunction is a contact problem due to oxidized terminals.
Shown is the replacement of the coolant temperature sensor in the radiator; the sensor in the thermostat housing is removed in a similar manner.
New coolant will be required to complete the job.
1. We prepare the car for maintenance and repair.
2. Disconnect the wire terminal from the negative terminal of the battery.
3. Drain the coolant.
4. To access the sensor in the radiator, remove the front bumper trim.
5. Press the lock...
...and disconnect the wiring harness connector from the sensor.
5. Visually check the condition of the sensor terminals and the wiring harness block.
6. To remove oxides, treat them with a cleaning and protection agent for electrical contacts.
7. Using a slotted screwdriver, remove the spring retainer and, pulling, remove the sensor from the hole.
The sensor connection is sealed with a rubber ring, which must be replaced.
We replace the sensor in the thermostat housing from the top of the engine compartment.
Sensor in the thermostat housing: 1 - wiring harness connector; 2 - spring retainer
Note: You can check the sensor by measuring the resistance at its terminals at different temperatures. The resistance values should be approximately the same as those indicated in the table. Otherwise, the sensor is faulty.
| Temperature,°C | Resistance, kOhm |
| -40 | 93 |
| -20 | 21.50 |
| 1 | 7.00 |
| 20 | 2.80 |
| 40 | 1.20 |
| 65 | 0.50 |
| 85 | 0.25 |
| 100 | 0.16 |
Recommendation.
- You can use hot water to heat the sensor, taking measurements as it cools.
- To connect the device to the sensor, you can use two pieces of thin PVC tube about 10 mm long. The tubes are put on the sensor terminals and the device probes are inserted into them.
8. Install the sensor in reverse order. Before installation, moisten the sealing ring with coolant.
9. Fill the system with coolant. We start the engine and make sure that there is no coolant leak from under the sensor, otherwise we fix the problem.
[Original version of the article on the website ChevyMan.ru]