The thermostat of my Opel astra g 1.6 16v 100cv 4 doors does not upload

Good afternoon, my name is Oscar for a long time that I have been observing that the thermos of my Opel Astra 1.6 16V 100cv 4 doors, does not go up and realized after making a 200 kilometers trip, which I should go up, but nothing goes up, or walking, or when I start it.

I think it's the thermostat, which doesn't work well, but I wanted to ask here before.

I also do not know what thermostate ask why it is not clear to me what is the exact model of my car.

This is what he puts in the technical tab: Motor: Brand: Opel/gm

Type: G-Z16xe

Someone could help me with my problem and tell me if it is thermostat, which one should ask for the model of my car.

Thank you so much....