How to replace a Coolant Temperature Sensor (CTS) on a TDI 150

[sockpuppet]

1) Remove engine cover
2) Compress the two clips and move them inwards so they are located on the plastic hose
3) Twist the plastic hose and ease it from the airbox and the pipe and remove.



4) The sensor location should now be visable



5) There is a small gap at the bottom of the the clip (Marked 1 on the picture) on the underside of the CTS location where a screwdriver can be inserted to wedge the clip downwards.
6) The sensor may now come out and you will lose about a litre of coolant
7) Push the release away from the sensor (Marked 2 on picture) and it should unclip.
8) When getting the new sensor, by the clip and rubber washer.
9) Clip new sensor into the electrical connector, then put the rubber washer on and place in CTS housing.
10) Push in whilst fitting the clip
11) PULL THE CTS TOWARDS YOU WITH YOUR FINGER as it is easy to miss the clip groove on the side you can't see.
12) If there is no movement of the CTS then fill the coolant and check there is no leak from the new sensor
13) Put the plastic hose back and secure the clips.
14) Start engine and run, fill coolant everytime it drops after 4 or 5 times it should stay level.

 

[Dan FR]

2 tips:

1. Remove the coolant cap to release system pressure, then tighten it to reduce amount of coolant lost.
2. Ensure the old O-Ring comes out with the sensor as they sometimes have a habit of staying put, meaning the new sensor won't secure correctly and you end up losing more coolant than needed

If you do this correctly & quickly you lose next to no coolant (mine barely dropped below the minimum)