Why is engine over heating and coolant reservoir boils?

Engine overheating and boiling coolant in the reservoir can occur due to several reasons, including low coolant levels, a malfunctioning thermostat, or a failing water pump that disrupts the circulation of coolant. Additionally, a blocked radiator or damaged hoses can prevent proper heat dissipation. If there's a head gasket leak, it can also lead to combustion gases entering the cooling system, causing pressure buildup and overheating. Regular maintenance and checks can help prevent these issues.