Hi,
On my MK1 Uno Fire 1L the needle has always pointed to 70 degrees on the temperature gauge under normal driving conditions. Being stuck in traffic the temperature rises to a little over 90 and the fan cuts in. The interior fan that blows hot and cold air into the car stopped working about two months ago and I had to change it for a new one. In doing so I had to drain the coolant and take out the heater core. When I put everything back together the temperature started to rise to about 80 degrees while driving under normal conditions. I changed the thermostat, the water pump, made sure there was no air in the system, flushed out radiator etc.... but to no avail. Since I changed the thermostat (genuine Fiat) the temperature needle now rest half way on the gauge at 90 degrees. I brought it to my local mechanic and he thinks that is normal but now when I stop in traffic the fan cuts in after less than a minute surely this is not normal? Can anyone advise?.

70 °C is not normal operating temperature - the engine is undercooled (higher consumption, less-than-efficient heating etc.), which is often the case of a busted thermostat. Fitting the thermostat the other way around compared to other cars is, IMHO, the manifestation of common sense by Fiat designers - undercooling the engine when the thermostat fails is surely not as dangerous as its overheating.
Normal operating temperature is at about half between the 70 °C and 90 °C marks. It can easily fluctuate depending on the ambient temperature, the way the wind blows etc., but it should not fall below 70 and raise above, say, 100.
If you are nervous about the fan cutting in frequently (which, in urban traffic, is IMHO normal), you can check your coolant level.
As long as the thermometer needle does not cross the border of the red portion, I would not worry about it.

i agree with enda.
mine also have 'normal' (its very relative, eh?) working temp at about 90 degree. when it comes to one mark (on temp.gauge) over normal, the fan cuts in until two marks below and then it shutdown. so the fan keep the temp between -2 and +1 mark(s) of normal temp (about 86-92).
my daily driving is on heavy traffic, and i preferred to have normal temp that way since the fan is working less frequently (saving more its lifetime) and engine temperatur is about normal. oil life viscosity (is this a proper term?) decrease in dealing with constant heat i believe, but i dont really care much as i change it frequently at about 4000-5000km.
also i change some cable routes for cooling. thermoswitch and fan is connected directly to baterry but a fuse and relay added to prevent current overloads.
my car is mk2 91, 16 years old! some electrical connection need more attention as the socket become corroded and cable starts to brittle.

yeah, i would worry until the needle temp is crossing the redline. actually, its easy to spot when you got it just a bit higher than usual but no device had been changes recently, then well, something going wrong with your cooling devices.

Thanks for your input guys. When I took out the old thermostat it was stuck a little open so that must account for the 70 degree operating temperature. I really hate the electric fan cutting in as this is one of the most anoying sounds. Wish the temperature was 70 degrees again.

sure uno fan sounds very loud but it blows add a little boost.. lol,
i think you should check the soundproofing also and everything that should be sealed (doors, cable passage etc).

The sound proofing is fine, the fan is too loud In my opinion.


I discovered what the overheating problem was. Headgasket gone. I had it replaced a few days ago and it is fine now. I didn't need to get re skimming done as no damage was done.

Gerry

Good to hear that your Uno is now sorted, but was it changing the heater core that caused the head gasket to fail?

gholian said:

The sound proofing is fine, the fan is too loud In my opinion.

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Yes it is loud isn't it... but as my father always said, it's when the sound stops that you should be worried

If you're really keen, you could obtain the fan, resistor, and sensor from an Uno Turbo (or certain other 'performance' FIATs/Lancias) and set that up - the Uno Turbo has a two-speed fan. The sensor has two wires, so the first speed kicks in at a lower temperature than the second speed. The lowered speed is made possible by a resistor ('spring'-like coil) in the fan shroud. The fan itself has a quieter motor and larger blades. Yet another example of the kind of detail engineering done to the Uno Turbo (that makes it so much more than an Uno with a Turbo! )

I discovered what the overheating problem was. Headgasket gone. I had it replaced a few days ago and it is fine now. I didn't need to get re skimming done as no damage was done.

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Like Chas, I'm quite surprised by this?
The temperatures you reported in the first post are normal, and it is normal for the fan to kick in after a minute of idling while stationary. So on that basis, I wouldn't have suspected a head gasket failure. Perhaps there's some more information that we didn't see

On the other hand, if the head gasket was marginal due to age, and the new thermostat increased the running temperature, that would possibly have finished it off. BUT the increased temperature is a good idea - the engine will run more economically, it is better for the oil (dries out condensed moisture), and the heater will work more effectively in the winter, so windows demist faster etc. An Uno with a stuck-open thermostat would barely warm up at all in the wintertime... unlikely to reach 70 anyway.

Anyway, good to hear it's all fixed.

-Alex