Which item does NOT make up components of a cooling system?

The alternator is not a component of the cooling system; it is part of the electrical system in a vehicle. The primary function of the alternator is to generate electricity to power electrical systems and charge the battery while the engine is running. In contrast, the cooling system is responsible for maintaining the engine's operating temperature by circulating coolant to dissipate heat.

The components that do make up the cooling system include the radiator, which helps cool the coolant by allowing air to flow through it; the pressure cap and reserve tank, which help maintain the proper pressure and fluid levels; and the water pump, which is crucial for circulating the coolant throughout the engine and radiator. Understanding the specific functions of each component is essential for diagnosing cooling system issues and ensuring proper vehicle maintenance.