If the engine overheats, there is most likely an air pocket/bubble in the cooling system. Then the cooling system must first be professionally bled.
A permanent and by Opel officially recommended remedy against the formation of new air bubbles in the cooling system is the installation of 2 check valves in two hoses leading back to the expansion tank.
We supply 2 of the original spare parts (Opel /GM / AC Delco), on the accessories market there are also fake versions of these valves available!
The installation can be done in a few minutes even by inexperienced persons. Installation instructions are enclosed with the valves.
Scope of delivery:
2 pieces original / GM Opel check valves
Opel /GM / AC Delco 9013001