Description

Strengthen your Subaru’s cooling system for demanding driving with a high-pressure radiator cap engineered by STI. By increasing the system’s operating pressure, this cap prevents coolant overflow under extreme conditions, helping to maintain optimal coolant levels and thermal stability during spirited driving, track use, or in high-temperature environments.

Product Highlights

• Increased Pressure for Overflow Prevention: This cap raises the cooling system’s opening pressure from the standard 108 kPa (0.108 MPa) to 130 kPa (0.13 MPa). The higher pressure raises the coolant’s boiling point and prevents it from expanding out of the overflow tank under the intense heat generated during aggressive or competitive driving.

• Supports Sustained High-Performance Driving: Engineered specifically for “sports driving or circuit driving,” this cap is a critical supporting component. By helping to retain coolant volume under extreme thermal loads, it contributes to maintaining consistent engine temperatures, which is essential for reliability and power output during repeated hard use.

• Maintains System Integrity Under Stress: The higher pressure rating helps keep the coolant in the core radiator and engine passages where it’s needed for heat exchange, rather than allowing it to be displaced into the overflow reservoir. This promotes more efficient cooling system operation when it’s under maximum stress.

• Direct, Performance-Focused Upgrade: As a genuine STI component, it’s a simple, bolt-on upgrade that addresses a specific weakness in the stock cooling system for high-demand scenarios. It’s an essential, inexpensive piece of insurance for any enthusiast pushing their vehicle.

Technical Specifications & Application

This is a direct replacement radiator cap with a higher pressure rating, designed as a preventative performance upgrade.

Key Details:

• Product Name: STI High-Pressure Radiator Cap

• Key Benefit: Increases system pressure to 130 kPa (0.13 MPa) to prevent coolant overflow during high-performance driving.

• Application: For specific Subaru models. Must verify compatibility with your vehicle’s cooling system design and pressure tolerances.

• Pressure Rating: 130 kPa (0.13 MPa) Opening Pressure.