If one technician repairs a leaking heater core and another replaces it, who is correct?

In this scenario, both technicians can be considered correct, depending on the context of the repair needed for the heater core. Repairing a leaking heater core is often a valid solution if the damage is minor and repairable, such as fixing small leaks or sealing connections. This can serve as a cost-effective option, especially when the rest of the heater core is functioning well and does not require complete replacement.

On the other hand, replacing a heater core may be necessary if the leaks are significant or if the core has extensive damage, corrosion, or buildup that cannot be effectively remedied through a repair. In such cases, replacement ensures the functionality and reliability of the heating system, preventing future leaks or failures.

Therefore, both actions are valid depending on the specific condition of the heater core and the best interests of the customer. Each technician is making a choice based on their assessment of the heater core's condition and the needs of the vehicle.