Hey guys, hopefully this is a really simple question!

How many temperature sensors are on the Skoda Fabia early 2003 OHV model? I need to replace all of them. I can see one, but my friend suggests there may be another.

Thanks,

Nick

What do you mean by 'temperature sensor'? I can think of five off the top of my head: the coolant temperature sensor, next to the thermostat; the radiator fan temperature sensor on the back/side of the radiator; the exterior temperature sensor behind the front bumper; the evaporator temperature sensor for the air-con, inside the dash, and; the cabin temperature sensor that's part of the air-con control panel...

I'm guessing it's the first one you're asking about, which can be replaced independent of any of the others:

http://briskoda.net/forums/topic/61178-fabia-coolant-temp-sensor-how-to/

While you're in there, it may be worth making sure the thermostat housing hasn't broken (you will be able to see the thermostat spring through the hole if it has). This will require quick hands or a partial drain of coolant, and it's worth getting Jorily's aftermarket part rather than the official one...

HTH

Thanks for the response!

My apologies for the idiot nature of the question. Of course there are tons of sensors everywhere In this case I meant the coolant temperature sensor bolted onto the engine. My friend suggested that it was possible that there are two on the engine.

If there is a problem with one it will show up on VCDS. What issues are you experiencing exactly? The common one to fail is the one by the thermostat which measures the coolant temp.

There is a value in measuring blocks for temperature of the intake manifold, I am not sure how this is measured, the only sensor I am aware of in the intake manifold is the MAP sensor at the back.

Edited 27 September, 201015 yr by anewman

Thanks for the response!

My apologies for the idiot nature of the question. Of course there are tons of sensors everywhere In this case I meant the coolant temperature sensor bolted onto the engine. My friend suggested that it was possible that there are two on the engine.

OK, there are two in this case - the one by the thermostat, and the one in the radiator. You can usually tell if the first one's gone, as the temperature gauge on the dash stays 'cold'. If it's an intermittent fault, you may just suffer rough idling. As for the one in the radiator, this controls the cooling fans, and you will be able to tell if this doesn't work by seeing whether or not the fans kick in if the car's left stationary with the engine running for any amount of time.

As anewman says, a proper fault code scan will give an accurate diagnosis, but the tests above are obviously free!

HTH

Thanks for all your help guys.

I'm looking to maintain my own car rather than spend lots of money for garages to guess what the problems are. I have the help of a good friend who knows a lot more than me, and I have my own tool kit now. I am a genius software developer, and I think if I truly apply myself I can be a relatively mediocre car mechanic (which would be an improvement on all the paid-for mechanics I've encountered so far!).

If you're interested, I'm pretty certain that the temperature sensor on the engine has failed. This is mainly because the temperature gague stays put most of the time on the left. Also, codes are popping up. I have a code reader that tells me that the input is low. Also, the idle is very rough and in fact it idles quite high the first few minutes of the day. If that isn't enough evidence, we examined the existing sensor and water has managed to get through it.

Anyway, I have ordered a new sensor and am going to install it in a few days!

Nick

Edited 28 September, 201015 yr by Nicholas Hill

If you ordered the sensor from Skoda directly it won't come with a new o ring and horseshoe clip (I haven't had those clips break on me though, but I like to renew o ring seals like that just to make sure it won't leak in future). Replacing the temp sender is a very easy job, easier than replacing the air filter

Forgot to mention that another common fault on the Fabia 1.4 mpi's is the clips inside the thermostat break. When the temp sender is out stick your finger in (you should be doing this when the coolant is stone cold anyway) and see if you can wiggle the thermostat. If it wiggles the clips have broken and you need a new thermostat. There is a revised version available from Jorily where the clips will not break. But I myself have decided to go back to the original genuine one for a few reasons. First it appears the Jorily thermostat runs a degree or two cooler than standard (probably not an issue really). When I flushed out my cooling system recently I noticed a lot of water still goes through the thermostat to the radiator when cold and the car takes a while to heat up (it was fine up until I flushed the cooling system so not sure if I have broken something inside it or dislodged the clip somehow will have to investigate that when I replace it), I have also had some issues with it taking longer to start when warm (disconnecting the temp sender makes it start straight away and replacing the temp sender did not fix it.)

Edited 28 September, 201015 yr by anewman

The Jorily 'stat on my wife's car runs just fine? The OEM replacement we got first time round broke within a fortnight, though! Pot luck, perhaps?!?

One things to add is that the threads the screws go into can get mashed up pretty badly if you have to take the screws out and put them back again a few times (as I did). However, a few slivers of cable tie shoved in there fill the gaps nicely, and have held for a good couple of years now...

Thanks Apogee,

The sensor arrived today. I ordered it from Jorily who sell parts dirt cheap - that was quite a shock! The sensor came with a horse shoe clip and rubber band. When I get back from work today I will switch the sensors and perform a quick wiggle check on whatever is under the existing one.

If it works I'll let you know!

Nick

I installed the new temperature sensor yesterday and now when idling the temperature gauge rises. I drove the car to work today and the gauge reached the 1/4 mark so I was a bit worried. It is however a cold day, and I was able to touch the engine after my 30 minute drive so perhaps the sensor is reading correctly.

One thing I noticed is that the horizontally mounted spring that I discovered under the sensor during its exchange wiggled under my finger and seems quite loose. Can anyone tell me the purpose of it, and what would go wrong if I left it as it is?

Perhaps I will need to replace that too but I will need to look at my Haynes manual first to see how difficult it is.

Nick

The fact you can see the spring at all indicates that your thermostat housing has failed as well as the sensor. As it fails open, the engine doesn't warm up properly, as shown by your (now working) temperature gauge only going to 1/4.

You should be able to get the housing without the sensor easily enough, and the easiest way to replace it is to pop the car up on axle stands, take off the under-tray, drain the coolant using the tap by the radiator bottom hose, unclip the hoses into and out of the thermostat housing, and replace either the whole housing or just the part the thermostat clips into.

If you know for a fact that your coolant is less than five years old, you can re-use it, otherwise you should replace it. Halfords ready-mix RED coolant is the right stuff, but you will also be able to get it as concentrate from a factor (G12 or TL774D spec). If you're putting new in, make sure the heater is on hot so that the matrix drains, and give the radiator bottom hose a good shake to get the last bits out.

When re-filling, make sure you expel any air by keeping the heater on hot and running the engine until the radiator fans come on. Once it's cold again, top the coolant back up to max.

HTH

That's really insightful Apogee, thanks very much!

Would this device suffice?:

http://cgi.ebay.co.uk/Skoda-Fabia-1-4-Mpi-Thermostat-BRAND-NEW-Replacement-/290470738461?pt=UK_CarsParts_Vehicles_CarParts_SM&hash=item43a167ba1d

It seems like a difficult job, and I do not have axle stands (yet!).

May I bother you with the following additional questions:

1) What do you mean by under tray?

2) Is the radiator tap obvious to locate and operate?

3) Will I need to purchase new hose clips, and are they easy to take off and replace?

4) Is it obvious how to unclip the old thermostat and replace it with the one shown in the above link?

5) By "heater on hot" do you simply mean the the internal cabin heater?

The reason I am asking the above dumb questions is because I don't want to be half way trough a procedure and then render my car useless! However, fixing it myself would give me great satisfaction - and of course respect for those willing to help.

Thanks once again,

Nick

Yes, the part you linked to is exactly what you need. In answer to your other questions,

1. The undertray is screwed onto the underside of the car, running back from the bumper. It's held on by six Torx screws, but a small flat-head screwdrive ought to do. You won't be able to get at the drain tap with it still on, but it's...

2. ...obvious once you're under the car with the tray removed.

3. As long as you're careful, you can re-use the clips. Locking pliers work well if you don't want to buy the special tool (you don't need it!)

4. With the hoses off, all you need to do is remove three screws to swap out the thermostat. Give the mating surfaces a good clean with a damp cloth, and use the new O-ring provided.

5. By heater on hot, yes I mean the cabin heater. Don't worry about messing things up - it's not a difficult job with the car in the air (but please use ramps or axle stands and not just a jack!) Once the job's done, keep a close eye on the coolant level until it stabilises, and you should be fine.

Then all you need to do is give yourself a pat on the back!

It's easy enough to do without a jack or ramps, but you risk spilling small amounts of coolant on the ground, and it getting dirty - not an issue if you don't intend to reuse it. It is easy enough to get to the drain tap without jacking or removing the under tray, but coolant flows out of it slowly and it is difficult to get a catch bowl underneath where it flows. Easiest way IMO is small washing up bowl or underbed storage box (latter probably better), and mole grips. Remove the hose which comes from the bottom of the radiator, from the pipe at the bottom visible just in front of the engine. Use mole grips to push the two tabs on the clip together (as standard it is fitted with the tabs underneath, I refit them with the tabs on top so they can be removed in future without laying on the ground), move it away down the pipe and pull the hose off the pipe (having placed bowl ready to catch coolant). Bear in mind once the hose is removed coolant will flow out of the hose and the pipe and do so with some force, and if the tray is left on it will flow over that too. As you have hold of the hose you can try direct the flow into the bowl. Be careful that the clip does not spring out of the mole grips, as with some types of mole grips it is difficult to refit the larger clips if they have fully retracted.

Haynes says to bin the standard clips and use worm gear drive type. I STRONGLY disagree with Haynes, the original clips are the best and are the only ones that should be used. If used with care they are as easy, if not easier than worm drive type to use.

+1 about the clips - Jubilee clips pinch! IME, I tried doing it with the car on the ground, but ended up spilling loads - a large, flat box as suggested above would have done it, or potentially you could park with the nearside wheels on the kerb if you live on a quiet street...

Thanks again guys,

As I wait to receive my new thermostat, could anyone enlighten me as to what all of the effects of overcooling are?

Some effects could include increased fuel consumption, fans not getting warm quick enough to clear your windscreen, and on short journeys oil not getting warm enough to get rid of water build up leading to mayo on the oil filler cap.

I received the thermostat today and I've looked at it enough to have a reasonably good idea how I could replace the old one properly - I think it can actually be done!

Anyone have any idea how much this would have cost to fix in total if I had used a garage? (ie: replacement of temperature sensor, discovery of failed thermostat and replacement of that and a complete replacement of coolant).

anewman: Any idea how much additional petrol would be used by overcooling? (ie: 1%).

Nick

Seeing how you generally get charged in either half-hour blocks or quarter hour blocks for labour at a garage, I reckon it would be 45-60 minutes' work, so around 40-60 quid. Since you got the parts and coolant retail, you probably won't have saved much there.

As for running cold, I reckon the extra fuel would amount to more like 15-20% (at a guess) as the ECU aims to have the engine running at such a temperature where the coolant is at a steady 90 degC, since this is apparently the optimum temperature for efficient running. Certainly, replacing the MAP on my wife's car (measuring air temperature rather than coolant temperature) gave a healthy increase in MPG.

Anyone have any idea how much this would have cost to fix in total if I had used a garage? (ie: replacement of temperature sensor, discovery of failed thermostat and replacement of that and a complete replacement of coolant).

Yep the job is a pretty simple easy to do one. At a garage you would pay for the parts etc, probably £50 for thermostat and temp sender, £15 for coolant. And then maybe 1 hour labour which could be as much as £50 maybe more. TBH most garages are useless and would tell you the thermostat is okay just because they've idled the car a bit and the fans are warm. A little bit of knowledge about it being a common problem helps

Only thing is not to do the nut/screw things up too tight, should be little more than finger tight, otherwise you take the threads off the plastic housing.

Official time for replacing thermostat is 45 minutes, apparently. Since the 'stat and the sensor come as a pack from the dealer, I think you should assume they'd be done together if the garage understood the problem. Even so, that's anything up to 40 quid you've saved yourself, so give yourself a pat on the back!

The Jorily 'stat on my wife's car runs just fine?

I have since found out what was wrong. There is a fragment stuck in the thermostat wedging it open, will boil it up now and try an extraction. So it will have been caused when I flushed the system through I presume.

Edited 6 October, 201015 yr by anewman

Axle stands arrived today, just need coolant now! (Assuming 5 litres diluted required)

Excellent. Five litres should be plenty, but remember to keep some back for topping-up once the air's purged from the system. With the car in the air, it's a very easy job...