Technical heat gauge goes from 1/4 to just over 1/2 when idling

[OverheatingPalio]

When idling for a while in traffic heat gauge goes from 1/4 to just over half, the moment I start driving it goes back to 1/4. What could be causing this ?
Could it be the fan not kicking in or the water pump or the radiator ?

 

[FiatPuntoMad]

What temp did it used to get to ? I have no experience of this car, but the vast majority of fiat's, and tbh most other car manufacturers, the water temp dial heats up to halfway (or just under/over)

As long as the temp doesnt rise above 1/2, or near enough 1/2 i would imagine the fan is working.

Sounds like you have the same issue as my punto. A sticking thermostat.

Whats happening is your thermostat is more than likely stuck up open, so when your driving and accelerating, due the the increased rev's the engine is pumping more water through the radiator, but the thermostat isnt closing to compensate for it increased airflow through the radiator, hense why the water temp drops to 1/4.

I have had 3 thermostats from car parts shop now and all have done the same thing, so for my next i will be getting a genuine fiat one.

 

[FiatPuntoMad]

Also, its not a 1.2 8v by any chance is it ?

If so, probably same engine as my punto and they seem prone to dodgy thermostats.

 

[Most Easterly Pandas]

Sounds like you need to replace your thermostat as its sticking open and causing over cooling

 

[OverheatingPalio]

In reply to above response:

Yes, its a 1.2 8v (Fiat Palio 1.2 Active - phase ii, South Africa).
Some countries like Brasil it's called a Palio Fire Economy 1.0 8v).

Also, as mentioned - when idling for a while in traffic heat gauge goes from 1/4 to just over 1/2, sometimes I have to switch the heater on to keep it at 1/2 or lower.
Once I start driving it goes back to 1/4.

Question 1: is it normal for car to go to 1/2 or slightly over 1/2 while in traffic ?

Question 2: could the fan (not coming on) or a weak or leaky water pump be causing this in traffic ?

Question 3: as mentioned - replace your thermostat as its sticking open and causing over cooling.
(I replaced thermostat last year October with genuine FIAT part).

 

[OverheatingPalio]

How can I test if fan is switching on once temp gauge gets to 1/2 or just over 1/2 ?
How can I test if water pump is not weak or leaky ?

 

[FiatPuntoMad]

1/2 way is normal running temp, as long as it doesn't go above half way (or just over) nothing to worry about.

Just get the car up to temp, open bonet and observe fan. Fan usually kicks in to keep the temp at the 1/2 mark. Obviousy if it doesnt kick in temp will run above half way.

However, it shouldn't be dropping to 1/4 as your driving.

 

[OverheatingPalio]

Fan usually kicks in to keep the temp at the 1/2 mark, if it does not temp will run above half way - this happens to me sometimes in traffic so I can assume fan is suspect or temp. sensor is suspect.

It shouldn't be dropping to 1/4 as your driving - it happens everyday so I can assume thermostat is sticking open and causing over cooling.

 

[FiatPuntoMad]

I suppose its possible for the thermostat to become 'sticky' and stick in both closed and open positions before 'freeing' its self, though they usually either become lazy, or stick either open or closed.

Could be an issue with the fan not kicking (causing the temp to rise above 1/2)

And an issue with the thermostat sticking open ( causing over cooling and it to drop to 1/4)

I would start with the thermostat if im honest, cheap to buy and not a hard job. Just make sure its a decent brand/quality.

 

[Most Easterly Pandas]

Just make sure its a decent brand/quality.

:yeahthat:

Probably best to get OEM from dealer direct, they're cheap enough

 

[OverheatingPalio]

:yeahthat:

Probably best to get OEM from dealer direct, they're cheap enough

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Eventually solved the problem (touch wood as the English say).
Last week Thursday (2013/04/04) I replaced radiator and flushed cooling system properly, now heat gauge is always between 1/4 and 1/2. In heavy traffic it goes to just below 1/2.