Changing the Coolant Temperature Sensor

airboxIn an effort to improve the MPG from the 106 I decided to replace the Coolant Temperature Sensor on the thermostat housing. This sensor is used to ‘tell’ the ECU what temperature the coolant is at. If the sensor is sending erroneous readings to the ECU, the ECU may inject more fuel as it would during a cold start.

You’ll need:
1) The Part number for my 98 model was 1920.3F from Peugeot.
2) Flat headed screwdriver
3) Cable tie cutters
4) Spare Cable tie
5) 19mm spanner

To access the sensor you need to remove the airbox. This is a simple job.

Undo the jubilee clip on the air pipe at the top rear of the engine bay. Then disconnect the breather pipe going to the airbox. Finally remove the cold air feed at the front of the bay connecting to the airbox – you may need to cut a cable tie to remove this. Wiggle and pull the airbox upward and out.

Now you should be able to see the green sensor on the right hand end of the cylinder head.

Now ensure the coolant is cold, so you don’t burn yourself, removing the sensor.

Coolant Temperature SensorUnclip the loom by pressing in the spring clip and withdrawing it from the sensor. Unscrew the sensor using a 19mm spanner and replace with the new sensor.

Refitting is the reverse of removal, replacing the cold air pipe cable tie if necessary.

I will be keeping an eye on the MPG over the next couple of tanks to check if I see any improvement.

Don’t forget the MPG calculator here to you’re having issues with fuel economy.


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