NISSAN 21710-VB80B Coolant Expansion Tank

The genuine NISSAN coolant expansion tank (part number: 21710-VB80B, alternative OEM part number: 21710VB80A) is an essential component of the vehicle's cooling system. This premium quality part ensures optimal operation and pressure balance within the cooling circuit.

Technical Features and Functions:

• Material: High-grade, heat- and pressure-resistant, semi-translucent plastic construction designed to withstand the chemical properties of coolant and high temperatures in the engine compartment.
• Design: Engineered to factory OEM specifications with mounting points and hose connections for an accurate, leak-free fit.
• Pressure Management: Safely compensates for coolant volume changes caused by thermal expansion, preventing excess pressure buildup in the system.

Role and Importance of the Coolant Reservoir:

During cooling system operation, the coolant heats up and expands. The expansion reservoir (TANK RESERVE) temporarily stores this excess volume of fluid and returns it to the system as the engine cools down. This maintains a continuous, closed cooling circuit and prevents air from entering the system, which could otherwise lead to engine overheating.

Typical Signs of Failure:

• Hairline cracks or visible fractures in the tank wall caused by aging and thermal cycling.
• Coolant leakage around the reservoir or at hose connections.
• Unexplained and persistent drop in the coolant level.
• Discoloration, embrittlement, or brittleness of the plastic material.