26452AG001 Subaru CAP RESERVOIR CP, Price: 9.23$, Weight: 0.014kg

Coolant Reservoir Pressure Cap for Subaru Vehicles

This small but critical lid seals the expansion tank in your Subaru’s cooling system. It keeps the coolant clean, controls system pressure, and helps your boxer engine hold the right temperature under load. Built with heat-stable plastic and an oil-resistant rubber seal, it’s an OEM-grade fit and finish ✅.

Why you need this part

The reservoir cap maintains a closed, controlled circuit so coolant can expand and contract without sucking in dirt or losing fluid. It prevents evaporation, keeps the level stable, and supports consistent heater performance in winter.

How it works ️

Inside the cap are tiny valves. As the engine warms, pressure rises; the cap vents excess to the overflow path. When the engine cools, a vacuum valve opens to draw coolant back, avoiding hose collapse and air pockets. The result is steady pressure and reliable flow.

What happens if it’s broken ⚠️

Cracked plastic or a hardened seal causes leaks, air ingestion, and unstable temps. You may see coolant smell, white crust around the tank, weak cabin heat, fluctuating gauge, or overheating. Hoses can flatten after shutdown, and the water pump may cavitate, risking head gasket stress.

Fitment and tips

Designed for popular Subaru models (Impreza, Forester, Legacy, Outback, WRX) using an expansion tank. Replace the cap whenever you service coolant or see residue. Always match pressure spec to your vehicle.

Installation advice

Cool engine only. Clean the neck, inspect the O-ring seat, then hand-tighten until snug—no tools. After a short drive, recheck level and look for seepage. Simple part, big protection.