Technical Bravo SX 80 Strange Temperature

[geosta]

Hello,
I'm new here so Greetings to all the members!

I own a Bravo SX 80 model 2001. Lately I have the following problem:

when I drive the car in the city, after some time, and when I am slowing down to park the car, the temperature gauge goes up, almost to the red, then comes a little down and up again.

The strange thing is that, when I press the button that closes the window, the temperature gauge goes down.

Another, even more, stranger thing is that when the a/c is on, the temperature stays always in the normal range, just below the center of the gauge.

And at night, when I turn off the lights, the gauge goes back to the middle, when I turn them on, it rises immediately.

These strange things happen...

The car works like a charm, it turns on immediately and it has no problems while I drive it...

Any ideas???

 

[Neverth]

Know problem with the temp gauge.
Strongly slamming on top of the dashboard may fix it for a while.

Or the gearbox ground or some other grounding point is corroding.

 

[geosta]

Thank you Neverth for your response.
Do you think that this explains why the temperature never goes high when the a/c is on?

 

[bluejohn125]

In the UK we did not get this car with AC, but I think maybe the radiator fan is not working properly. Normally this comes on in city driving. But if the AC is on then the fan will turn to cool the AC condenser, and will also cool the radiator and therefore the engine.

On my Rover 75 there is a common fault.. the fan has a 2 speed control so if the radiator is hot the full voltage is switched to the fan motor and it runs at full speed. But if driving normally with AC on the fan runs at half speed because a resistor is switched in to drop the motor voltage. But the standard original resistor usually fails, so the half speed fan does not work and so the AC condenser does not get cool.

 

[bluejohn125]

So maybe your temp sensor controlling the engine fan cooling has failed, or something in this area.

 

[olliefromuk]

Hi did you get to the bottom of your problem. It seems like it could be an electrical/sensor problem however does anyone know if this could be a thermostat issue, staying partially open and not opening fully perhaps?

 

[varesecrazy]

Hi did you get to the bottom of your problem. It seems like it could be an electrical/sensor problem however does anyone know if this could be a thermostat issue, staying partially open and not opening fully perhaps?

Actual wavering temperature..YES..

A temperature gauge being driven by use of other electrical devices..NO

do you have a 1.2?

My jtd weekend did similar.. on odd occasions

 

[Mike1alike]

Yes, the thermostat staying partially open could cause this problem.
And also, maybe a clogged radiator is causing it.

 

[olliefromuk]

I have a 1.6 and it takes a loong time to reach the optimal temperature, and when it gets near it sometimes drops right down suddenly, also the gauge isn't reading properly, which is evident from banging on above the cluster. So hopefully when i change the thermostat and temp sensor this weekend will be cured. I think in my case the radiator isn’t clogged because it tends to stay cooler than usual.

 

[varesecrazy]

You have a choice there :

Drain all coolant (and flush with water until it runs clean)

Or leave rad cap on and lose around 0.5 litre of coolant

A new thermostat should make a big difference

 

[olliefromuk]

Ok, yeah I have bought some new coolant so I will probably drain and flush the system. It will hopefully save making a mess of the engine bay! Hope so. Thanks. Is there a way of limiting air pockets when refilling or is it straight forward?

 

[Mike1alike]

Is there a way of limiting air pockets when refilling or is it straight forward?

A way is to have the front wheeles on higher ground. Open up the air vents and top it up. Close the vents, put the cap on and star the engine. Let it run a while, I think it's better when thermostat opens up, stop the engine and check the level. Also, open up the airvents again, if coolant leaks, you are good, if it dosen't, top up until coolant comes out, it will come out on one vent first, close that vent, put some mor till the second vent gives you coolant, close the vent, check the level, put the cap and that is it.

 

[varesecrazy]

Ok, yeah I have bought some new coolant so I will probably drain and flush the system. It will hopefully save making a mess of the engine bay! Hope so. Thanks. Is there a way of limiting air pockets when refilling or is it straight forward?

This GUIDE has 4 pages of written instruction.. and a link to dave 's Guide too

https://www.fiatforum.com/punto-mk1...2l-8v-fire-similar-radiator-system-gars3.html

Personally :

Nowadays I leave the rad cap OFF

Heater box set on MAX HEAT

vents OPEN

Drain by lower rad hose



Flush as desired



Fill until hoses are full and a squeeze of the hose makes a dribble at the vent.. THEN close the vent

Restore fluid level to MAX.. Leave cap OFF

and start engine.. you probably see the level drop a little.. as pump starts

Then will creep up as heat builds

Once it all feels HOT.. switch off engine

Once cooled restore level to max.. it will need a cupfull at most

BUT .. check level every few days..as it will self.bleed little pockets with use

Tips:

The bleed screws are now 'Ancient Plastic'.. so potentially brittle

They employ an o.ring to seal .. so dont need to be 'spanner tight'


The cooling fan does a good job..

Level will drop significantly as it cools the fluid.. then rise again as it absorbs heat.. so check levels COLD

 

[olliefromuk]

Ok thanks for your responses, I’ll give it a go this weekend ?