I have got to replace my coolant sensor and I know they are cheap to buy but would like to know how bad it is to change and what tools I need to do it.

These are pretty straightforward to change, but must be done on a stone cold engine! (i did my first one approx 4 hours after the car had been driven and the coolant was still ##kin hot!)

Tools needed:

Medium sized phillips/pozi drive screwdriver,

Small flat blade screwdriver

Pliers (possibly)

A 10 year old child or SWMBO who has small hands and forearms! (or be prepeared for some loss of skin on you arms or arms!)

Parts needed:

1x S059919501A temperature sender (sensor)

1x N90316802 O ring

SG012A8GM1 G12 coolant (you will loose some coolant when you remover the sensor, how much will depend on how quick you are!)

Possibly also a replacement horseshoe clip (i didn't buy one) if you snap the old one getting it out - more likely in the winter when the plastic clip will be brittle.

Skin graft, plasters, bandages!

Im not going to do a full walk through as there are numerous available on the internet already (search for 'coolant sensor replacement' for any of the VAG marques)

But on a MKI (1.9 TDi 130 PD) Superb / Passat they are located here:

You can see the (new green) sensor circled above, the old sensor will be black if it hasn't been changed before)

Remove the two caps marked 1 and remove the two phillips screws underneath, then pull the whole cover upwards. Then you 'just' need to slip your arm down the side of the engine (from the front), unplug the wire, remove the 'horeshoe' retaining clip (pulls down), remove the old sensor - note the O ring will probably not come out with the sensor so poke your finger in the hole and remove the old one, then push the new sensor (with a new O ring already fitted onto the sensor) into the hole, refit the clip and push the plug back on ......... simples!!

Now what you will struggle to find info on is how to remove the wiring plug from the sensor, this is a piece of cake when you know how, but a bas###d when you don't!

What was that?

Oh you want to know how they come off?

Simply push the plug onto the sensor a bit more whilst inserting a small flat bladed screwdriver into the rectangular hole of the plug and lift this tab AWAY from the sensor (towards the wires) and it will pop off easily.

HTH

Thx Gizmo

BTW its in different place on the2.5 V6. It's under the engine cover on top of the engine near the front.. HTH

Removing the airfilter box (10mm bolt to the wing, disconnect the MAF electrical connection, the large ~100mm hose to the MAF and the small ~10mm hose to the back of the air filter box, plus the assosciated intake plastic pipes) makes this job much easier.  

 

I think on an auto like mine it is impossible without doing this, as the EGR cooler and its hoses further block access from the side.

I just changed my Ed100 CTS a couple of weeks ago, took no more than 10 mins from start to finish.

 

Removing the airfilter box (10mm bolt to the wing, disconnect the MAF electrical connection, the large ~100mm hose to the MAF and the small ~10mm hose to the back of the air filter box, plus the assosciated intake plastic pipes) makes this job much easier.  

 

By the time I had removed those bits it would have been changed and the bonnet closed 

Yours is manual though, right?  Not sure what you were complaining about in your original post, then - I could drive a bus down there without the honking great big EGR cooler in the way... :-p

Yes correct it’s a manual, don’t get me wrong there is certainly a knack to it as your arm is fully stretched to reach the sensor, but it is doable.

 

No idea on the Tiptronic though!

Couldn't get horse-shoe clip off, grrr. Abandoned. ☹