Thermostat and engine temperature

[GeX]

Hi

I have noticed that my car (2002 Xsara VTS) that when holding a steady 70mph on the motorway that the water temperature will drop down to around what looks like 75c. The middle of the gauge is 90c.

The oil temperature sits at a fraction to the cool side of the 'the middle'. The oil gauge is not blessed with numbers so I don't know what it relates to.

Mildly concerned that my thermostat is sticking I looked in to getting a replacement. I have noticed that the temperature listed for the stat is 83c.

Is 83c the temperature it starts opening at, or is it fully open by then? Is it 'the norm' for the water temp to be anything other than the middle of the gauge?

 

[GeX]

clearly.. hence it cooling down - but a cooling system is supposed to maintain the engine at the 'correct' temperature. To me, that is around 90c - but I want to know what others think.

 

[GeX]

If the system is running properly, the car should get up to 90c and never deviate from that as I'm sure you know.

that is what I thought, but wanted to hear it from a few more people before I buy a new stat