Temperature problem at Seat Ibiza 6k

Hello! I have a Seat Ibiza 6k built in 12/97. On the way home from work today, the temperature indicator rose at once from quarter to three quarters. But since the red area was still a good bit away I did not worry about any more. But when I had to stop because of a tractor I suddenly noticed the smoke coming out of the bonnet. I directly bent into the dirt road and opened the bonnet. From the pressure compensation tank of the cooling water steamed and zi After only about 3 minutes the spook was already over again. A colleague who happened to come by took me with him and with the permission of the farmer I left my car standing. About an hour ago I drove to get my car. It was only about 10km and still I had to stop 3 times and turn off the engine because the temperature indicator rose again to three quarters. Since I just brought a bigger repair at the house behind me and now I slowly ran out of money i I’m afraid that this is a huge repair on the car. What do you think? Has this happened to you before? Does the temperature indicator in Ibiza actually go so wrong that the water already boils at three quarters? I always thought everything below the red area was fine.