2001 BMW 525i TEMP GAUGE

Each morning or after my car is parked for an extended period, the temperature gauge goes up to the red zone and then after 5 or so minutes would go back down to normal. The colder the outside temp the longer it takes to go to normal, please let me know what could cuase this problem. I recently changed the radiator, thermostat, water pump and associated accessories.

Thanks

Arron


As per above I did state each morning, meaning the engine would be cold, on moving off it would rise to normal then to the red zone stay there for about 5 minutes then back to normal.

Thanks