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Fabia coolant temp sensor - how to


ap0gee1978

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Blatting up the M1 in SWMBO's Fabia, I noticed the temperature gauge was stuck to the left and wouldn't budge. It came back to life after we switched off the ignition to fill up with fuel, which is a telltale sign that the sensor's on its last legs. This can apparently lead to head gasket trouble and all sorts, so here's how to replace it:

NB: There is now a printer-friendly pdf version attached at the end of this post!

You will need a small screwdriver, and possibly a socket set, depending on the model of Fabia. The part number is 06A919501A, and cost me GBP26.28 incl VAT.

NB: DO NOT DO THIS JOB UNLESS YOUR ENGINE IS ABSOLUTELY STONE COLD!!!

1. Take off your engine cover. On my vRS, you just remove the oil filler cap and pull. On SWMBO's 1.4 MPi, you have to remove the dipstick, oil filler cap, and the two nuts shown:

cts1.jpg

2a. The coolant temp sensor is here on a 1.4 MPi:

cts2.jpg

2b. ...and here on a 1.9TDI PD, on the right-hand side of the engine, tucked away, facing the back of the engine bay and with the socket release catch facing away from you! :doh: :

cts3.jpg

(This post shows where it is on the 1.4 16v, but, I've not done the job any other cars to say where theirs are. All the same, if you follow the fat coolant hose back from the radiator and along past the right-hand side of the engine, you ought to find it!)

3. Fortunately, as I was replacing the sensor on Mrs. Ap0gee's car, it's at the highest point in the coolant circuit, so I didn't have to drain the system. You might have to at this point...

4. Unclip the sensor from its plug, and separate the two:

cts4.jpg

5. Remove the circlip holding it in place:

cts5.jpg

6. Give the sensor a bit of a jiggle and it will come out:

cts6.jpg

7. The offending article:

cts7.jpg

8. Put the new sensor in, and put your car back together following the above steps in reverse order. It's a good idea to leave the engine cover off and start the car and leave it idling for a minute or so, just to make sure there are no leaks around the sensor. Once you're happy, you can put the cover on...

9. If you have access to VAG-COM, clear the fault codes. If not, the coolant system seems to work OK regardless, but warn your garage that it's been done, otherwise when THEY read the fault codes they may want to put in another sensor!!!

HTH :)

FabiaCoolantTempSensor.pdf

Edited by ap0gee
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  • 8 months later...

I saw your year old post and thought you might be able to help. I have a bit of an emergency with my Fabia 1.4.

I bought one of these sensors from eby and it looked identical. I fitted it but the warning light stayed on. Then I drove it a few miles and the coolant warning light flashed and beeped and smoke came out of the grille.

I parked and walked 5 miles back home.

Should I replace the old sensor? Should I get some G12 coolant from somewhere just in case?

I've no idea if there is any serious damage done until I get back to the car.

If it is possible you could reply asap to [email protected] I would be grateful.

Kind regards

David Callinan

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I've just found this article too

The coolant temp gauge went to the left, came back to normal a few times but is now stuck at the left. The 'electronic engine management' light also came on, is this normal? If so will it go out when the sensor is replaced?

What is the resistance of the sensor when cold?

Thanks

Tim

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Going to try and answer these two queries done in a one-er. Please be aware I don't know anything like as much some on here, so there may be other (better) responses...

I saw your year old post and thought you might be able to help. I have a bit of an emergency with my Fabia 1.4.

I bought one of these sensors from eby and it looked identical. I fitted it but the warning light stayed on.

When the sensor went on my wife's car, it didn't actually make any warning lights come on, it was just that the temperature gauge didn't work. AFAIK, the coolant warning light works off a different sensor, but you don't say whether this was the light that 'stayed on'... Was the the engine management light (see below)?

Then I drove it a few miles and the coolant warning light flashed and beeped and smoke came out of the grille.

I parked and walked 5 miles back home.

Should I replace the old sensor? Should I get some G12 coolant from somewhere just in case?

Was this the light that was on before? Or did the coolant warning light come on in addition to whatever light was on before? From what you're saying about 'smoke' coming out of the grille, could it have been steam? If so, I suspect there's a leak somewhere - possibly from around the sensor if it wasn't a good fit. If you stopped as soon as the warning light came on, you may be OK but you'd need to top up with coolant as you will have boiled some off...

I've no idea if there is any serious damage done until I get back to the car.

If it is possible you could reply asap I would be grateful.

Kind regards

David Callinan

If you have overheated the car (it does sound like it :o ), then there's a possibility that you may have damaged the heat gasket or even the head itself. You should be able to drive the car once you top up the coolant, but I wouldn't recommend taking it any further than the NEAREST garage - and if you've got breakdown cover, get it towed... I'm sorry I can't help more, but it's all a bit beyond my knowledge, I'm afraid... :(

I've just found this article too

The coolant temp gauge went to the left' date=' came back to normal a few times but is now stuck at the left. The 'electronic engine management' light also came on, is this normal? If so will it go out when the sensor is replaced?

What is the resistance of the sensor when cold?

Thanks

Tim[/quote']

As I said in my response to David, there weren't any warning lights when it happened to my wife's car, but the other 'symptoms' suggest that the sensor's gone. If the sensor failure has caused the engine management light to come on, replacing it should make the light go out I think, but the fault code will still be stored (hence what I said in the original post). I'm afraid I don't know the resistance of the sensor though... :o

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Hey, me again :o

When I used my car today (first time since me and my Dad have a look at the sensor) and the coolant temp gauge worked intermittently. When i parked for work the gauge was working but the 'electronic engine management' light was still on. However when i left work later the gauge still worked but the management light was not on (was on at start up so light still working). Does it have a long and short-term memory or something, so when a problem is fixed or fixes itself the light goes out but the code stays in the long term memory?

half way home the gauge stopped working, so its not fixed :(

I found this topic.

http://www.briskoda.net/forums/fabia/temperature-gauge-fluctuation/66771/

It all seems to be familiar (even same engine (1.4MPi) and one same reg (02) as one of the cars mentioned). Though when they sometimes say thermostat, do they mean the coolant temp sensor?

Is the coolant temp sensor used by the engine management system to control the reeves at idle when cold, etc?

My car has had some interesting quarks when starting at certain times (nothing series). Could this be connected?

Thanks

Tim

PS - I've found the resistances of the coolant sensor in my Haynes manual (they were a little hidden) If anyone wants/needs to know just ask :)

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I found this topic.

http://www.briskoda.net/forums/fabia/temperature-gauge-fluctuation/66771/

It all seems to be familiar (even same engine (1.4MPi) and one same reg (02) as one of the cars mentioned). Though when they sometimes say thermostat, do they mean the coolant temp sensor?

You're right - it does sound similar to the problems you've been having! As regards thermostat / temp sensor, the sensor sits within the thermostat housing. Since doing my technical guide, I've heard from a few people that it's not much more difficult to replace the 'stat housing (sensor and all) in one go, as the thermostat can sometimes fail at about the same time as the sensor, so you can "kill two birds with one stone". Plus, you can get all the bits as a pack from the dealers, for not much more than just the sensor. I think Fordfan posted somewhere earlier on the thread how to do it. As regards your other queries, I don't know enough about the diagnostic system to say whether fault codes have an "expiry". Certainly, when the EPC light came on on my wife's car, it stayed on after I switched off and back on again, but wasn't there the next day and hasn't returned since. You can always see if there are any members near to you who will give your car a check-over with VAG-COM (for a few beer tokens, of course! ;):) ) As for the sensor controlling revs etc, it certainly does (as do a number of other things, too!). Obviously the engine is more efficient when warm, so amongst other things, it will provide input for the equivalent of the choke on a carburettored car. As the engine may think it's cold when it's actually warm, this will affect the fuelling and thus the performance...

HTH :thumbup:

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  • 2 weeks later...

Good info on the temp sensor as our 1.4MPi is just starting to play up with engine revs at idle & intermittant temp gauge operation.

Have been wondering whether rev probs due to engine management system? Will try replacing sensor first.

On another note regarding the EPC light. Ours recently came on with no apparent cause i.e no loss of power etc. Turned out to be the brake light switch. Replacement part 8 quid from dealer.

No need to reset as it sorted itself out when engine turned on (self check)

cheers

shrump

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  • 1 month later...

My coolant temp sensor is on perminantly however the temperature is where is should be i have replaced the sensor to no evail. i took it to a garage and the man put it on the computer the 02 sensor was broken, this was fitted and the light went out horay, :thumbup: then comes today the sensor is back on and im angry :finger: Bloody car

any help would be great

ps. my lights are flickering also is this a electrical problem or a short circuit ?

many

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My coolant temp sensor is on perminantly however the temperature is where is should be i have replaced the sensor to no evail. i took it to a garage and the man put it on the computer the 02 sensor was broken, this was fitted and the light went out horay, :thumbup: then comes today the sensor is back on and im angry :finger: Bloody car

any help would be great

ps. my lights are flickering also is this a electrical problem or a short circuit ?

many

When you say 'flickering' do you mean like a candle, or do you just mean dimming slightly from time to time? A bit of dimming is normal due to the amount of power used by the power steering, however an actual flicker is usually the result of a faulty steering angle sensor. Have a search on here for it (not to be confused with the 'yaw angle sensor' that's part of the ESP system!)

Fixing this might help get rid of your warning light too! :)

HTH :thumbup:

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  • 1 year later...

Hi all!

I'm from Spain. I have a 1.4 mpi fabia and I'm also suffering intermittent gauge operation. Thanks to this manual I've successfully replaced the coolant temp sensor... but it is still not working as it should: I still get intermittent gauge operation, reduced fuel autonomy...

Do I need to replace the whole thermostat housing to solve the problem? What do you think?

Thanks in advance!

Edited by mclatilla
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You can check if the thermostat is OK by removing the sensor and looking in the hole. If you can see the thermostat spring, then the housing has failed. Since you have already replaced the sensor, you would only want to replace the half that the thermostat itself sits in, and you can get replacements where the thermostat is held in by a circlip instead of plastic lugs, which should last longer!

Hope this helps! :thumbup:

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  • 1 month later...

I've had the intermittent temp sensor on my 02 fabia I bought a few weeks back so the garage took it back to replace it. On the way there the coolant warning light came on, I checked and the coolant level was ok and the guage came up to normal when I turned back on but still the warning light. This hasn't cleared even after they replaced the temp sender so now they are going to replace the header/expansion tank. Does this sound right?

The car runs fine otherwise but I'm wondering if they will be able to fix this secondary fault or whether this is just going to go on until the warranty runs out and cost me in the long run. The engine management light came up a couple of times when the guage had misbehaved but always went out afterwards.

I'm hoping that all this is just because the car had stood on their forecourt for a month unused as the reverse light switch packed up too.

I've found the posts here really helpful so far.

Thanks

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The coolant level sensor is a different fault to the one covered here, but it is also quite common. Replacing the tank is the correct way to fix it, so I don't think you have anything to worry about! :thumbup:

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  • 3 weeks later...

Thanks ap0gee for the superb info. I had the same symptoms. I did my 51 plate 1.9tdi successfully today. The water pump on the Diesel lump is in a slightly different place, far right of head with the sensor underneath the pump and difficult to see so had to be removed by feel. So having pics from ap0gees post helped. Its difficult to remove wiring in situ, so I found it easier to pull the sensor retaining clip to remove it still wired first, then undo the connector afterwards as there is slack in the loom. You lose about 2 pints of coolant. Dont forget there is a rubber O ring in the hole or on the sensor....dont let it fall into the waterway ! Replacement was fiddly and by feel too, but with patience easily do-able. Cheers for the helpful post :) By the way, all my parts (temp sensor, o-ring, clip, Heater motor resistor pack etc) have been sourced from Jorily Skoda who have provided an excellent & speedy service.

Edited by bobtastik
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  • 1 month later...

I took mine out today just to have a look before i actually bought the part and the coolant came gushing out but with my quick reactions I put it straight back on so not much came out.

Ok I did Ignore the advice on not doing this unless my car is stone cold.

So is this the reason of the advise and will it come gushing out if I take it out when cold?

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Ok I did Ignore the advice on not doing this unless my car is stone cold.

So is this the reason of the advise

Nope - hot water scalds!

and will it come gushing out if I take it out when cold?

Yes it will, but at least it wont scald you!

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I'd guess that as it is reasonably high up in the water system, and if the car is cool, then maybe surprisingly, the system will be under a partial vacuum. That is what I found when I changed one on my V6 Passat (petrol engine). In fact I'd go further and say that due to me waiting until the engine was cold, and the system being a bit below ambient pressure, I had quite a bit of trouble extracting the coolant sensor as I was fighting against the seal sticking to the engine and sensor, and the vacuum effect, and the fact that on that engine, the sensor location is a bit difficult to reach. I had to ease it up using two screwdrivers while not being able move either very far - another reason to leave the connector on until the sensor is out (as long as you don't abuse the wiring too much)!

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Right I fitted mine this morning and you do not have to drain your coolant if the engine is cold.

It's a pretty easy job the hardest bit is getting the clip off.

When you buy it from skoda they should supply you with a new rubber o-ring to seal it. make sure to remove the one already there as mine stayed in rather than sticking on the old sensor.

Good Guide! Thanks.

Edited by fabiash
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  • 3 weeks later...
You can check if the thermostat is OK by removing the sensor and looking in the hole. If you can see the thermostat spring, then the housing has failed. Since you have already replaced the sensor, you would only want to replace the half that the thermostat itself sits in, and you can get replacements where the thermostat is held in by a circlip instead of plastic lugs, which should last longer!

Hope this helps! :thumbup:

Finally I bought the thermostat at Jorily, replaced it, and now it's ok again :)

It's the second time I got my thermostat changed, last time was 100000 kms ago.

Thanx a lot indeed!!!! :thumbup:

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  • 3 months later...

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