Will exceeding the coolant maximum level have any impact?

[DiMaggie]

Overfilling the coolant does not have any significant impact on the engine. This is because the expansion tank is equipped with a drain pipe that serves as a pressure relief mechanism when excessive coolant causes overpressure. The excess coolant will also be discharged through this drain pipe. Additional details are as follows: 1. Insufficient Coolant: If the coolant level drops below a certain threshold, it will no longer be able to meet the required capacity for proper engine cooling. If coolant is not replenished and the vehicle continues to be driven under these conditions, the engine temperature will rise rapidly, significantly increasing the risk of piston scuffing or engine seizure. 2. Two Types of Pressure Relief Mechanisms for Antifreeze: Some systems feature an overflow pipe in the auxiliary tank, while others have a one-way pressure relief valve on the cap of the auxiliary tank or radiator. Additionally, the auxiliary tank (a white plastic container) is typically cylindrical in shape, allowing it to accommodate a relatively larger volume of expanded antifreeze.