Mileage: 150,012KM
Do It Yourself: Yes
Difficulty: Easy

This is considered second time the unit leaked. The first round, rectified using a non-spec o-ring due part availability. This time around, I managed to secure the correct o-ring size and dimension.

 Some engine oil residue on top of thermostat housing. The grey connector underneath the black hose is the sensor

Sensor removed

Cleaned up all the gunks

Fixed the new O-ring

Job completed in less than 30 minutes