No coolant temp on dashboard

[Brian60]

This started last week, a 2006 Xsara Picasso, 1.6 petrol 16 valve. The temp gauge stays at zero, however there is coolant in the engine, it gets hot, the radiator is hot - the overflow tank is not, that stays cold. The car is driving ok, just yesterday I did a 70 mile round trip at speed with no problem at all.

If I have driven and turn the car off and wait a minute or so then turn the ignition back on. The temp gauge goes all the way to the top for a few seconds before dropping back to 0 and even if I then drive the car it still does not move.

So is this looking like the sensor, or the thermostat? How do I determine which thermostat would be required? looking on one of the online dealers it lists 3 different ones with no way of telling which is fitted.

Many thanks everyone, its not often the Picasso gives me problems.

[wheeler]

The temperature sensors normally fail safe & tell you that the engine is overheating when it isn't. Best way is to get it on live data on diagnostics & check out the coolant temperature. Even the cheap ebay ones will read coolant temp.
What is the last 8 digits of the VIN?

[Brian60]

Sorry couldn't stay on page I had to pop out. This is the last numbers of the VIN. 25775880.

[wheeler]

Just want to check that VIN is correct, your location says Spain but this is originally a UK vehicle?

Looks like the thermostat come with the housing. £113 + vat in the UK.

[Brian60]

Thanks Wheeler, that is correct. Its a UK vehicle that we exported around 2015 - it was cheaper to do that and re register it than buy another car in Spain. Of course it has its drawbacks, go to a distributor and ask for parts and its a 'Noh' however if I leave the car for them to fix at their charges its a 'Si'. So when I do need more than generic parts I try and source from the UK and ship them over.