Maybe this is the wrong place to post this so please do move it to where it belongs if needed.
Ok well i had the dreaded temp sensor issue where the gauge showed running at 50 or 70, never 90. Now i was told i had a faulty waterpump a while ago by a muppet, even though i proved him wrong in the back of my mind i always wanted to resolve issue with the temp sensor.
What you will need:
Green temp sensor with new seal and new clip.
Flat head screw driver
G12 and water to top up.
Right step 1
Take the dip stick out and then remove the engine cover with a 10 mm socket.
Unclip bost hose on the upper top left side and pull to one side.
Locate the temp sensor, on the 1.9 tdi its just under the bost hose on theleft hand side of the engine, it will have 4 wires on a connector on the back of it.
Remove expansion tank cap.
Remove the sender connector from the sensor. Not as easy as it sounds, My first attempt to do this was a total failure and it took me nearly 1 month to re attempt. The connector is on pretty tight to say the least, it will come off but the angels you have to work with are not the best so here is how i did it. I turned the sensor so the i can see the clip part of the connector then with a flat head screwdriver put it in the tiny gap on the clip an slowly tuen to relase the connector. It may of just been mine but for some reason the connector would not budge if i was to pressed the clip section on the connecor, hence the use of a screw driver.
Again with a screwdriver slowly prise out the securing black clip that holds the sensor in the engine.
With the connector out of the way remove the sensor from the engine. Coolant will flow out, i did not see the point trying to quickly plugging the hole but you can if you want. I just wanted to make sure i got the job done right. Once the coolant is out locate the seal thich should be in the hole on the engine, then remove it.
Fit the seal to your new green sensor and insert it,fit the new locking clip and attach the connector.
Top up you coolant with g12 and water if needed(trust me you will need to later) refit everything else. and run the engine while checking for leaks.
Once you are happy you have no leaks take the car for a little drive to check the sensor works as it should, it took me about 8-9 mins of driving to get the gauge to read 90. Keep an eye on the gauge as mine did dip for a bit then returned to 90.
Get the car back home and check coolant level again. I had to top up again as i created a small airlock.
, hense the slight dip in temp on my short run.
Hey presto Job done. I would say dont rush,stay calm and tripple check everything.