Felicia temp gauge - sensor replaced but gauge sluggish

[feliciaman]

Hi All.

Just bought my 99 Felicia 1.3L manual (mpi engine) a few days ago - see 'Introduce Yourself' forum - and have a question about the temp gauge.

When I got the car I realised whilst driving it home that the temp gauge needle was resting on the stop and didn't budge. Fortunately the previous owner had left a Haynes manual in the boot so I investigated cooling system probs and found that the temp sensor, which also provides temp info to the ECU, could be faulty.

I grounded the temp sensor black wire as per the manual and the gauge deflected. So, duff sensor and ordered an aftermarket replacement and fitted it - amazingly easy, for a change. Ran the engine up and eventually the needle started to lift. Waited to see if the cooling fan would cut in and it did, so all seemed well.

However, went off for a proper drive y'day and the gauge barely registered and took 5-6 miles to do so. It was quite a warm day although the breeze was cool. I found the highest the needle would go was the 70 mark, which seems a bit low for a hot engine.

So, I am wondering if perhaps the thermostat is stuck open and water is getting out to the radiator too early, keeping the engine from reaching operating temp longer.

Or are Felicia gauges just a bit dodgy and never register that high anyway?

Would appreciate your thoughts/suggestions.

Thanks all.

P.

[KenONeill]

That's almost certainly a stuck-open (or even missing) thermostat.

[feliciaman]

That's almost certainly a stuck-open (or even missing) thermostat.

Thanks for the speedy reply, Ken.

Where on the gauge should the needle rest when the engine is at normal temp, would you say?

I'm guessing at somewhere just below the 110 mark?

P.

[gardenerchris]

i had the same issue with my 1.3mpi....replacing the thermostat sorted the probem. The temp gauge always sat just under half way under normal conditions....just rising in traffic. Also the mpg was better after sorting the problem.

[Lofty79]

Usually around 90 or so. +1 on thermostat

[feliciaman]

Thanks all - will look into getting a replacement stat - probably on fleabay, unless you can recommend a better place?

P.

[KenONeill]

Get a genuine one; fleabay specials have been known to cause troubles too.

[feliciaman]

Well, this has turned out to be a bit of a sorry tale of woe.

As there seems to be some uncertainty about the right stat for the car, I thought I'd open up the housing and take a look at it.

Note: no need to drain down the entire cooling system, you'll only lose a pint or so and you can catch most of it in a large yoghurt pot or similar (preferably when there's no yoghurt in it ). Three 8mm nuts hold the housing in place and as it's plastic-to-plastic they're coarse-threaded bolts.

Imagine my surprise to find the housing cavity empty - no sign of a thermostat and the retaining lugs that take the metal clip that holds the stat in place, broken - as predicted in another thread on this subject. No wonder the engine wasn't getting up to the right temperature, with the coolant being pumped around the rad from the word go and nothing to regulate it.

Another thread speculated that with the coolant never reaching the right temperature the ECU might keep the mixture richer and so burn more fuel (just hope it hasn't contaminated the catalytic convertor). Why would someone not bother to replace the stat - and housing if necessary? This car's been regularly serviced, according to the record; I only bought it on Wednesday.

Anyhoo, back to the story. So I did some searching online and then ringing around locally to see if I could get hold of one today. For some reason the stat on its own is very expensive - £37 from a Skoda Dealer - and yet the entire housing - that's both halves - with stat already in place *and* temperature sensor (doh! bought one of those separately when I diagnosed the sensor as being faulty) was £44.12 inc VAT (genuine VAG part) from a VAG parts specialist (Skoda dealer didn't have one in stock but quoted about £47 all in. Mysterious.

The part number for this assmbly is 042121111A.

I did find the stat alone listed online for about £24.45 delivered, but since my housing was broken that wouldn't have helped. I did find a guy in London on Gumtree who's selling a part assembly, so if you're reading this because you're looking for the parts and you're not in a big hurry, get in touch with him as it's a good price at just £25 plus whatever he wants for P&P.

http://www.gumtree.c...ostat/111704522

Took no time to put everything back together, top up the system and give it a test drive and now the gauge is stabilising where it should, around half-way and hopefully with the right engine temp the ECU won't be over-fuelling and wasting it.

This may make you chuckle wryly: when I was test driving the car, at Felthorpe Cars near Norwich, just in case you're tempted by one of their vehicles, I commented to the owner that the steering seemed a bit heavy, not realising that this model Felicia never had power steering. He said that the car had been standing for a while so maybe the pressures were down. He promised to check them before I came back for the car.

When I collected the car later that day, it seemed incredibly light and skittish at the front, with very little grip in corners - nothing like when I'd driven it earlier. It was almost a bit scary tbh.

The next morning I thought I'd better check the tyre pressures and was astonished to find that the front tyres had been inflated to 90psi - yes, you read that correctly *90* pounds per square inch, as against the normal 29psi. So this idiot had solved the heavy steering by putting three times as much pressure into the tyres as necessary, As a result, I noticed that one of them was actually bubbling out air through a perished crack in the sidewall! if it had been wet or icy I could well have crashed and been injured or worse! What a bl**dy cowboy!

I wonder if he removed the faulty stat as well??

Do you think he should be reported to Trading Standards? Hard to prove, of course and in any case I have found TS to be largely unhelpful and powerless when dealing with rogue 2nd hand car dealers in the past, including one I had to take to court (another waste of money, even though I got judgement).

Thanks to all for help and suggestions - much appreciated.

P.

Edited 5 October, 2012 by feliciaman

[robk1]

Hi Feliciaman, my temp gauge tends to vary typically between around 1/4 and just under 1/2, the later being the normal running temp. I may be wrong but it seems to link to ambient temp, running on the cooler end on a generally colder day. The difference is a little more exaggerated compared to the earlier days of ownership on this Felly

[feliciaman]

Just taken the car out for a run this evening and found that, once the car's up to temperature, the gauge steadily oscillates a milimetre or two either side of the halfway mark as you're going along. I imagine this is the gauge reacting to the thermostat opening and closing as the heat builds up in the engine, then falling as coolant is released into the radiator.

Probably if the gauge was better damped this wouldn't be noticeable, but hey, am I bothered? No, because I know I now have a properly-functioning cooling system.

Happy drives, one and all.

[feliciaman]

I was thinking about this overnight and wondered if the fact that the engine is made of aluminium (which conducts heat better and faster than steel) might have something to do with the fluctuations. When the stat opens for the first time after a cold start, a generous slug of cold water is released into the engine from the radiator and its pipework - that is obviously enough to cool the engine quite a bit for a few seconds, then the heat being generated catches up and the temp rises, as does the gauge needle.

On a vehicle whose engine has more thermal inertia, like the hefty steel and cast iron TD5 lump in my LR Discovery 2, there's much more thermal inertia and the metal doesn't conduct heat as well so when the stat opens, you don't really see any change in the position of the gauge needle.

Once the stat on the Felicia is open, its opening must vary with the temp of the water and that must affect the overall heat of the engine and the cooling system and hence the position of the gauge needle.

Make sense?

P.

[adurer]

You have to consider a few things:

1) the thermostat starts to open at 88 deg. C and it is fully open at 100 deg. C

2) the radiator cooling fan kicks in at 105 deg, C

3) the temp sensor has a low precision, some +/- 5% at least

4) the temp gauge itself is not made for NASA shuttle

So I hope you get my drift...

[uma1998]

thermostat i took mine out and thats what mine did i did this to give a bit more power tho

[feliciaman]

You have to consider a few things:

1) the thermostat starts to open at 88 deg. C and it is fully open at 100 deg. C

2) the radiator cooling fan kicks in at 105 deg, C

3) the temp sensor has a low precision, some +/- 5% at least

4) the temp gauge itself is not made for NASA shuttle

So I hope you get my drift...

Noted - can't expect an old car to behave like a modern one, still I have been pleasantly surprised so far and I can see why my son is so attached to his.

thermostat i took mine out and thats what mine did i did this to give a bit more power tho

Surely that isn't a good idea as with the coolant temp down the ECU will keep the mixture richer? Won't that lead to dirty spark plugs and increased fuel consumption?

P.

[uma1998]

no i had it set up to run that way and no fuel was better

[KenONeill]

no i had it set up to run that way and no fuel was better

I've got to ask; why do you think you'd get more power with a block temperature of 70C than of 90C? When answering, bear in mind that I actively know that a given oil would be more viscous, and hence absorb more power, at the lower temperature.

[J242]

i have 2 felly's, both X reg classics (1.3)

One 80ish K (odo broke) and broken thermostat, has been broken for years..

other has only just hit 10k and is in full working order.

the old heap is quicker and less thirsty. maybe thats why? ill have to try swapping the thermostats over and see what happens

[KenONeill]

i have 2 felly's, both X reg classics (1.3)

One 80ish K (odo broke) and broken thermostat, has been broken for years..

other has only just hit 10k and is in full working order.

the old heap is quicker and less thirsty. maybe thats why? ill have to try swapping the thermostats over and see what happens

Taking "X reg" as meaning 1998-99, I have to ask if the low milage car is suffering from cokeing, siezed rings, has ever even been up to full running temperature...

[J242]

2000, first registered 28/09/00 (the one with 10k) and 28/11/00.

Everything on it is sweet as a nut other than the electric windows closing rather slow and clutch squealing. (thrust bearing?) temp rises as should and engine is perfect.

other one makes a cloud of smoke when started, idles lumpy, engine rattles and shakes all over the place, clutch slips, tries to go sideways at the slightest whiff of a corner and the heaters never get warm but has been like that for ages. never left me at the side of the road and goes like stink. it refuses to die so will get a new lease of life

[robk1]

^ Some familiar characteristics of the ancient order of the Felly! But like you they've rarely ever left me on the road side over many years

[feliciaman]

Mine's a little rattly in the engine - sounds a bit tappety and occasionally there's a loud clicking sound from the engine, too, when it's just standing at tickover. Couldn't be a sticking valve, could it? Runs along very nicely otherwise.

I'm hoping the camchain is ok - *supposed* to last the life of the engine? The Haynes manual says they can become loose and noisy and need to be replaced at around 30k, which is worse than a rubber cam belt!

[feliciaman]

Update on temp gauge behaviour. During the winter I have observed that the temp gauge rises steadily to just above halfway at the start of a run, then suddenly drops down to about a 1/4 or so. I presume this is happening because the thermostat opens and all the cold water in the rad is dumped into the cooling system at once, so the engine temp falls quickly and the thermostat closes again.

Then the gauge starts to come back up, the stat opens once more and then the gauge falls back down, only not quite so far this time. This goes on several times, the drop gradually reducing, so that eventually the gauge settles around the halfway mark, moving a little up and down either side of the mark as you go along.

I imagine in some cars there's a bleed-off that always allows a little water into the radiator so it gets the chance to warm up before the stat opens so there's less thermal shock due to a big difference in temp between the coolant in the engine and the coolant in the radiator. Would you agree? Or has the felly got a bleed-through that may be blocked or not functioning in the case of mine?

Thanks guys.

F.

Edited 4 March, 2013 by feliciaman

[TeflonTom]

I think you've misinterpreted the function of the thermostat a little bit squire, it's not like a sluice which suddenly opens and all the freezing cold coolant rushes in, when it opens it does so gradually, the amount it opens is directly related to the temperature of the coolant pushing against it.

if your temperature is dropping suddenly it may be because there is an air lock in the cooling system somewhere

[feliciaman]

I think you've misinterpreted the function of the thermostat a little bit squire, it's not like a sluice which suddenly opens and all the freezing cold coolant rushes in, when it opens it does so gradually, the amount it opens is directly related to the temperature of the coolant pushing against it.

if your temperature is dropping suddenly it may be because there is an air lock in the cooling system somewhere

Well, it only happens as the gauge gets near to halfway, then it drops suddenly before starting to creep back up again, so I would say that this indicates the stat is opening fairly quickly - how else can it be explained - I can check for an airlock, sure - is the car prone to such things? I can get useful heat from the matrix before the gauge reaches halfway, so I wouldn't say there's an airlock in that part of the circuit, at least.

F.

[TeflonTom]

if your heater is hot then I'd say you don't have an air lock, it would be the heater that would be the cause of an airlock normally because it's at the highest point in the cooling circuit