I have a 1992 e34 520i that so far never gave me any major trouble, today i started the car and drove (in a traffic jam) and like 5 minutes later i suddenly noticed the temp gauge touching the red zone, i was feeling no changes in the engine or any noises or smells but nonetheless stopped the car immediately. I waited for it to cool down which took a long time and then opened the radiator to check the coolant level which was lowish but not empty, i slowly topped it up and restarted the engine and everything seemed normal, drove away and again, everything seems normal and no overheating. I then stopped in a parking lot and decided to let it idle for a while and again, the temperature started climbing so o turned it off but i noticed no smells, noises, smoke or changes in the engine. After that i again drove it normally with no overheating but after a few kms a warning light came on in my instrument cluster, a red circle with 3 small rectangles on each side, i checked the manual and it says its the worn brake pad light but all this just seems very strange. Anybody has any idea what i may be dealing with here?

Edit: btw i drove this car all summer and in some traffic jams while it was very hot outside and it never overheated, rn its winter and its cold outside so this also makes no sense to me