Coolant Reservoir / Radiator Overflow Tank for Nissan Pickups

This expansion bottle keeps the engine’s cooling system in balance. As coolant heats up and expands, it diverts excess fluid from the radiator into the tank; when the engine cools, it draws it back, keeping the system topped and air-free . Built from high‑temp polypropylene with molded brackets, it’s designed for durability through constant heat cycles and vibration.

Why this part is needed

A healthy overflow tank maintains correct coolant volume, prevents aeration, stabilizes operating temperature, and protects the water pump, thermostat, heater core, and head gasket. Clear walls and level marks make quick checks simple.

How it works

A small hose from the radiator neck routes hot overflow into the reservoir when pressure rises. As the system cools, vacuum pulls coolant back through the cap’s valve. The circuit stays sealed, corrosion is reduced, and coolant stays clean ✅.

What happens if it’s broken

Cracks, brittle nipples, or loose caps cause leaks, sweet coolant smell, puddles, and overheating. Air pockets trigger fluctuating temp readings, weak cabin heat, and can lead to warped heads or blown gaskets if ignored ⚠️.

Notes

Direct-fit geometry. Reuse a good cap if applicable, replace aged hoses, fill with the correct premixed coolant, and bleed the system for bubble-free operation ❄️.

Compatibility

• Truck
• King Cab
• Np300