DIY is not much more difficult than swapping the temp sender. You first need to drain some of the coolant, or all of the coolant and have some of the correct coolant to top up. You only really need to drain it to below the level of the thermostat. To drain there is a drain provided on the radiator, it undoes like a bayonet bulb (i.e. twist and pull out). The other way to drain is to undo the bottom radiator hose in front of the engine (needs mole grips to undo hose clip) - this position is easier to catch the coolant in a bowl without removing the undertray.

On the thermostat there are 3 bolt/screw type things holding it, undo these and remove the thermostat making sure to remove the loose bits left in the rest of the housing (there may be some coolant loss here if you did not drain fully). Remove the o ring seal (there should be a new one with the new thermostat to fit it with). When you put back the screws they do not need to be done very tight, otherwise you will destroy the threads in the plastic housing. All that matters is that it does not leak when running. Top up your G12 coolant mixed 50/50 with water to max mark. Refit the cap and run engine until fan turns on then off. Let it cool and top up as appropriate.

To fill the entire system you would need 2 1.5 litre g12 bottles. I usually dilute it with deionised water.

Edited 5 December, 201015 yr by anewman

An excellent how-to; thanks. Prior to doing this I strongly recommend that you check whether the connections are dirty. I've had all the symptoms that people have talked about (on my SDi) and was totally ready to follow this how-to. However, I thought that I'd check for dirty connections first. After having - eventually - managing to get the coolant sensor connector off, I sprayed both the male and female parts with DeoxIT, a cleaner used in the recording industry, plugged the connector in and out a few times, with a final spray for luck. The gauge has now been working normally and reliably for a couple of weeks. DeoxIT dissolves oxidation on electrical connectors, and cleans off any gunge. It also gives it a little bit of protection. I've used DeoxIT to fix my Fabia non working electric window switches (stripped down to the remote-control-like component parts) and the multi-switch on my Mercedes Estate. In all cases the fix has proved to be permanent. DeoxIT is not cheap. I bought my spray can about 4 years ago and it cost £13.95, but it lasts a long time. A quick Google came up with this supplier, but I'm sure it's available cheaper elsewhere (high-end hi-fi stores, professional recording suppliers). It also sorts out noisy volume controls a treat.

http://www.stoneaudio.co.uk/?google=592

I suspect that many electrical 'faults' are actually dirty connections, so it's well worth trying this first before getting your hands dirty and your wallet emptied.

Hope this helps.

The stuff sounds exactly like electrical contact cleaner - e.g. http://www.toolstation.com/shop/Automotive/Lubricants+Sprays/Contact+Spray+400+ml/d60/sd2795/p81507 In fact I am sure I bought it once from there and they gave me an equivalent product the same price called Motip Contact Cleaner, which had a picture of a mixing desk on the can. Might be a cheaper alternative to DeoxIT.

Using this stuff cured dim fog lights on a car I owned previously (they had been disconnected a couple of days so corrosion must have built up).

We have a 2003 Skoda Fabia 1.2 petrol AZB engine. It has been superb so far but over the last few months it has failed to start a few times. It was always after the engine was warm. The engine would turn over fine but just not fire. Eventually after five to ten minutes the engine would start and everything would be fine for a week or so and then it wouldn’t start again.

I do my own diagnostics with VAGCom lite software which is superb, saved a lot of garage costs. There was a fault with the engine coolant temperature sensor. I read on the internet that this can cause starting problems so I bought a new sensor on ebay for £7.50 and changed it. Very easy to do:

The sensor is at the top of the engine block on the side between the engine block and the battery, located on the large water pipe from the radiator. Remove the filter box on top of the engine for access. Remove the two wire cable connection on the sensor. The engine must be completely cold and remove the cap of the cooling water tank to make sure there is no pressure in the system. With the new sensor and O ring ready quickly remove the old sensor and O ring and put in the new O ring and sensor. I didn’t bother draining down the engine and only lost about 500ml of water and just topped up the tank. Reconnect the cable and that’s it.

Hopefully that will resolve the starting problem.

The sensor part number is 06A919501.

Of course check and clean the cable connection first!

Edited 5 March, 201214 yr by Richardskoda

Looks like this will be my weekend project, along with the million and one other things I need to fix on my Fabia. Great info here on making the 1.9 TDI sensor more accessible. I tried to get at this a feew eeks ago, but just couldn't get the darned connector off. Took off an air hose for better access, but still no joy. Undoing the circlip to remove the unit whilst still attached sounds like a much better idea. I was worried I might give it too much of a yank and rip all the wiring out of the connector with it in situ.

Any ideas where the coolant sensor would be on a Fabia 1.2 diesel greenline edition?

Another sensor hunt query - any ideas for the 2.0 MPI?

The radiator hoses aren't as obvious as pictured in the main guide (a few smaller hoses/pipes). I did find this, which look like it might be a temp sensor but it seems to have 3 pins instead of 2, so wasn't sure if it's the wrong one, or if the sensor on this engine uses a different part.

Cheers.

Another sensor hunt query - any ideas for the 2.0 MPI?

The radiator hoses aren't as obvious as pictured in the main guide (a few smaller hoses/pipes). I did find this, which look like it might be a temp sensor but it seems to have 3 pins instead of 2, so wasn't sure if it's the wrong one, or if the sensor on this engine uses a different part.

Cheers.

that plug is the air con sensor and not part of the coolant system.

Edited 11 February, 201412 yr by colzie64

As regards to the temp sensor I have changed these on both a felly and my furby and the immediate change in mpg is quite significant. On the furby an increase of 10-15 mpg .

that plug is the air con sensor and not part of the coolant system.

Ah, I see. Thanks colzie64.

I have an issue with my temperature gauge in that permanently sits halfway in between the correct 12 o'clock position and the starting position. Is that likely to be a coolant sensor issue?

 

I did replace it 3 years ago actually for the same blimmin issue and it seemed to sort it for a year or so but went wrong again. I'm wondering if it's something else? Any ideas?

Hello, I am new to this site and sorry for jumping in but I am also looking for advice.  When I got my we fabia classic  2002 my son said the temp sensor needed replaced which never got done (thanks son ).  The car temp guage never moved but car drove fine.  Three weeks ago after being out in the car I stopped at a shop and car wouldnt start when I got back in car.  Diagnostic showed fob needed recoded which I got done and drove great for two weeks now it starts when cold and after driving short distance stop car it doesnt start till cold again.  After reading google my mind is frazzled.  Can it be this sensor sending wrong info to engine saying it is overheating.  Thanks and again sorry for jumping in.

Many thanks to the OP for this how-to. You've just helped a student repair his car for a fiver all-in.

Skoda Fabia 1.9 TDi '54 plate (2004).

 

The biggest problem I've found is in getting a working seal when the new sensor is put back in.  Old rubber seal removed, new sensor with seal pushed back in place, retainer clip pushed on.   Filled coolant, it was pouring out (which I caught underneath).   Removd, O ring still there, pushed back in really firmly and squarly (this is hard to see on this tough-position-model , but since the original post we have phones with cameras to help the process!)

 

No leak initially..  Turn the engine over, system gets up to pressure, immediately starts leaking out again!.  Frustrating!

 

Now I'm out of daylight, and will try again tomorrow.

 

Just saying that doing this process on that 1.9 TDI model is a right pain.

 

 

My solution was:  put a little bit of grease on the new O-ring.  The ring is initially quite stiff and frictions up between the sensor and the inside of the hole which it's sealing when pushed in.  The petroleum grease allowed it to slip and slide snugly inside for a good fit and flawless seal.

Edited 2 May, 20188 yr by denigor777