Technical Active Eco 2010 Temperature guage problems

[Cjhamar]

So my Fiat Panda Temp gauge is acting like a yoyo.

It doesn't seem to know where it wants to be.
One min it's reading just under half way next I see it plummet to the quarter dot and then bounce back to the half way mark fir it to fall to the bottom and back to the quarter and back to half.

I've read some forums that say temperature sensor, I've read some that say thermostat. And some that say wiring fault.

So my first question is 'what's the best one to replace first?
Sensor or thermostat?'
My second question(s) is(are) where do I locate the two parts on the active eco 1.1.?

And finally where can I purchase the parts. ( I know euro car parts sell the thermostat but it lists 3 and I'm not sure which it is.

Any help is greatly appreciated.

 

[BigAdam]

I'd go for Sensor first, its easier to change, and a thermostat doesn't work all that quick.

Another issue might be an air lock / bubble floating around at the sensor giving you issues. Had that on a van of mine.

 

[jrkitching]

Thermostat is way more likely than sensor.

Thermostat failure is well known on these cars; the internal rubber seal perishes and allows coolant to flow when it should properly be shut. On a gently driven car in cold weather, even a small leak past the seal can prevent the engine reaching normal operating temperature.

Because the seal is buried inside, faulty thermostats can appear to be operating normally if given the boiling water test,

Fortunately replacement is straightforward, and aftermarket thermostats are cheap as chips.

Don't just leave it, if the engine isn't getting up to its proper temperature, the ECU will overfuel; you'll have increased engine wear, and rubbish fuel economy.

 

[koalar]

Thermostat and temperature sensor are housed in the same part after around 2009

how quickly is it falling

Does the engine check light come on

Is the coolant level maintaining a reasonable high level

Do you have a scantool that can read live data.

Are the heaters also blowing warm instead of hot

Does the top hose remain cold from a cold start for a few minutes grab the hose in your hand it should remain cold for at least 2 minutes

 

[Cjhamar]

Thermostat and temperature sensor are housed in the same part after around 2009

how quickly is it falling

Does the engine check light come on

Is the coolant level maintaining a reasonable high level

Do you have a scantool that can read live data.

Some times it says at a temperature and falls a bit slowly other times it bounces....
No engine light
Coolant is generally OK... topped it up once or twice in last 5 years but not much.
No scan tool unfortunately, my mate has one and looked at it not long ago but no fault codes

 

[koalar]

Some times it says at a temperature and falls a bit slowly other times it bounces....

Over seconds
minutes
10 of minutes

How far is the needle moving.

A video would be good. If not we need good descriptions. We can’t see it. The better the information the better the advise

No engine light

Strange the Panda has a built in safety feature. If the computer see the coolant temperature has passed over 60 degrees Celsius and then falls below 60 it put the radiator fans on full and engine check light on. Rarely a problem in sumner coasting down hill or up a slip road normally triggers it.

Coolant is generally OK... topped it up once or twice in last 5 years but not much.

Good at least we know coolant is constantly contacting the sensor

No scan tool unfortunately, my mate has one and looked at it not long ago but no fault codes

Shame as one that reads live data would tell us the same information the computers reading and we could tell if it’s different to what on the gauge

Does ever get to halfway on the gauge ?

 

[Cjhamar]

Over seconds
minutes
10 of minutes

How far is the needle moving.

A video would be good. If not we need good descriptions. We can’t see it. The better the information the better the advise

Strange the Panda has a built in safety feature. If the computer see the coolant temperature has passed over 60 degrees Celsius and then falls below 60 it put the radiator fans on full and engine check light on. Rarely a problem in sumner coasting down hill or up a slip road normally triggers it.

Good at least we know coolant is constantly contacting the sensor

Shame as one that reads live data would tell us the same information the computers reading and we could tell if it’s different to what on the gauge

Does ever get to halfway on the gauge ?

I'd say fluctuations are minutes.
Not fully hitting half way on temp guage then fluctuates between half and ¼. But occasionally drops to the bottom.

I have now got a thermostat and a coolant temperature sensor.
I'm hoping to fit it today at some point.
Just waiting for r'kid to bring some coolant and jubilee clips, before I take the plunge and drain the system.

I've seen videos that show removing the battery, ecu box, coils/doofers that send the sparks , The bracket that holds the coils....

And then I can get to the thermostat. And I'm assuming the sensor is to the rear of that at the back of engine bay.

 

[koalar]

Doesn’t your eco have a combo thermostat and temperature sensor on the right of the the cylinder head like my 2010 eco

This is mine not as obvious as this as take with a flash but you can see the electrical connector for the sensor on the thermostat housing

Here what my part looks like on eBay
Photo somehow at the bottom



It’s hidden under here

 

[koalar]

Just grab this like this

From cold there shouldn’t be any flow at the bottom of the hose for a couple of minutes if the thermostat is sealing properly

Just be aware the radiator fan can randomly come on if there is a problem

Keep your fingers clear, there’s plenty of room

It’s such a simple test for the problem described by @jrkitching

Yet rarely carried out

 

[Cjhamar]

Doesn’t your eco have a combo thermostat and temperature sensor on the right of the the cylinder head like my 2010 eco

This is mine not as obvious as this as take with a flash but you can see the electrical connector for the sensor on the thermostat housing


View attachment 415768

Here what my part looks like on eBay
Photo somehow at the bottom



It’s hidden under here
View attachment 415771
View attachment 415769

I don't believe so.
Here's a couple of photos, I can't get in properly...

My thermostat I presume...

My heat sensor I presume?

 

[koalar]

I don't believe so.
Here's a couple of photos, I can't get in properly...

View attachment 415773
My thermostat I presume...
View attachment 415774
My heat sensor I presume?

Correct