Basic components interchange, though 2.5Pi models use different thermostat ratings to accommodate the fuel-injected engine's specific operating temperatures.
Core blockages develop over decades; flushing helps, but eventual replacement restores cooling capacity for reliable long-distance motoring.
Modern coolants and silicone hoses improve reliability whilst maintaining original specifications; major modifications affect engine performance unpredictably.
Cable-operated valves seize with age; replacement restores temperature control and prevents coolant leaks into footwells.