This is a little walk through I did on another site for the 2.0T FSI. Most elements should be the same. Might help someone here.
1. 06A919501A 2pin temp sensor
2. N90316802 O-Ring
3. Retaining Clip (Can re-use old one, but worth getting a new one just in case you break it)
4. G12 Coolant
1. Remove intake/engine cover
2. Take off coolant reservoir cap (de-pressurises the coolant system a little im told)
3. Locate temp sensor on right side of engine block
4. Put your fingers around the side of the sensor about half way down it towards the engine block and
push the retaining clip off the sensor towards the engine bay firewall.
5. Have the new temp sensor with O-ring on it ready to install in one hand and pull out the old temp sensor with the other.
Coolant will pour out everywhere as soon as you pull out the sensor.
6. Hopefully at this point the old O-ring comes out with the sensor you’re replacing. Mine didn’t and I had to fumble around to find it with coolant going everywhere.
7. Install new sensor and secure in place with new retaining clip
8. Take plug off old sensor with a flat head screwdriver. Clip into place on the new sensor.
9. Top up with coolant, reinstall intake/engine cover and clear fault codes if you have them (I didnt).
You’re working on this side of the engine
Sensor in centre of picture.
Old Temp Sensor, retaining clip & o-ring