Torque Solution Cylinder 4 Coolant Mod for Select 2002-2020 Subaru WRX, STI, Forester, Legacy (TS-SU-585)

Fits select 2002-2020 Subaru Impreza WRX/STI, Forester XT, and Legacy GT. The Torque Solution Cylinder 4 Coolant Mod (TS-SU-585) is designed to address a critical cooling deficiency in the Subaru EJ engine platform. On factory configurations, the rear of the engine block near cylinder #4 suffers from stagnant coolant flow, which can lead to higher localized temperatures, knock, and ring land failure.

This modification taps into the coolant passage at the rear of the block and routes it into the heater core return line. By facilitating constant coolant circulation across cylinder #4, this kit helps normalize temperatures across all cylinders, improving engine longevity and reliability under load. This is a must-have upgrade for both daily-driven and high-performance EJ20 and EJ25 builds.

• Manufacturer Part Number: TS-SU-585
• Directly increases coolant flow at the rear of the block
• Reduces localized cylinder #4 temperatures
• Helps prevent knock and ring land failure
• Compatible with factory and aftermarket heater core lines