Which cap maintains pressure in the coolant system?

• A. Coolant Pressure Cap
• B. Serpentine Drive Belt
• C. Windshield Wipers
• D. HVAC System Odors

Answer: (A)

Maintaining pressure in the coolant system is handled by the coolant pressure cap. This cap is spring-loaded and seals the system, holding a specific pressure so the coolant can rise to a higher boiling point and operate efficiently without boiling. As the coolant heats and expands, the cap allows excess fluid to flow into the overflow or expansion tank, but it only does so when the pressure reaches its rated level. When the system cools, the cap reseals, helping prevent air from entering and maintaining consistent pressure. If the cap is faulty, pressure can drop, leading to overheating or coolant loss.

The other components listed serve completely different functions: the serpentine drive belt powers accessories like the alternator and AC, the windshield wipers clear the windshield, and the HVAC odors pertain to the vehicle’s climate control system.