In the past we have already drawn your attention to mounting the cooling fin in the correct position. A water-cooled classic does not have to overheat. Provided there is sufficient fluid in the system, the thermostat is working properly, the hoses are not leaking (also at the connections!), The radiator or the engine are not blocked by, for example, lime or rust. The possible blockage can be easily solved with sodium hydroxide, popularly known as caustic soda and available in supermarkets or at the drugstore. Easy to solve. Remove coolant, add caustic soda, add water and take a ride of a few hundred kilometers. Then drain, rinse and refill with coolant or add anti-freeze to the water. An important factor in this overheating process is also the cooling fin. In most cases, it must draw in air. Except for something like a Classic Mini. And if that cooling fan is installed incorrectly, everything is confused, the engine runs hot and you get from those stories "Such a thing always runs hot", there are specialists (...) who advise the hood with supports on the windscreen side open even so-called louvres to manufacture in bonnets.
Photo: "Warm" running of the motor has a cause. The cooling system can be clogged. You solve that with caustic soda. However, it is also possible that you have mounted the cooling fin incorrectly or have it assembled ... If you are not sure, keep a newspaper in front of the grill and gas. If the newspaper blows away, the cooling fan is mounted incorrectly ...