Engine Coolant Reserve Tank (Overflow Bottle) ?️

This reservoir is a key part of the cooling system. It stores extra coolant that expands when the engine gets hot, then feeds it back when temperatures drop. Without a healthy reserve tank, your cooling system can’t “breathe” properly, and coolant level control becomes messy and unreliable.

Why this part is needed ✅

As coolant heats up, it expands and needs a safe place to go. This tank prevents pressure spikes, reduces coolant loss, and makes level checks simple. It also helps keep air out of the system, which supports stable engine temperature.

How it works ⚙️

Coolant flows to the reservoir through the overflow hose when pressure rises. When the engine cools, vacuum in the system pulls coolant back into the radiator. The molded plastic body and sealed cap area must stay crack-free to hold proper level and prevent contamination.

What happens if it’s broken ❌

Cracks, warped necks, or leaking seams can cause coolant loss, overheating, and repeated low-level warnings. Air may enter the system, leading to poor heater performance, unstable temps, and possible engine damage if ignored.

Compatible Models ?

• 350Z