Hi everyone, New to this forum and I bring a problem with my 1999 Seicento Sporting 1.1

My coolant temp light is on even though everything else with the cooling system appears to be hunky dory.

I've recently replaced the temperature sensor with a new one but I still get the light when there doesn't actually appear to be anything wrong.

It comes on after only 5 - 10 minutes or so of running when everything appears to be just lukewarm.
When the engine does get up to temperature, hot water reaches the radiator and the heater core, and the radiator fan runs periodically. (NB I've also had to replace the radiator fan switch recently, but the light comes on way before the radiator gets hot)

If there is an air lock around the back of the block preventing coolant flow where the sensor is located, no amount of bleeding is shifting it.

What could it be? Any help is much appreciated!

Welcome to the forum

You've fitted a Cinquecento sensor. As the Cinq is fitted with a temp gauge (rather than just the "Oh crap" light) it sends voltages to the gauge at lower levels to provide analog readings. The Seicento specific sensor reacts at a specific level, so if you fit the wrong sensor the light will react too early.

That makes sense. Thank you

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