Mishimoto Aluminum Radiator 2002-2007 WRX / 2004-2007 STI

Whether you daily drive a stock STI or push a modified WRX through rallycross, maintaining an efficient cooling system is essential to the longevity of your flat-four. The factory radiator’s plastic end tanks are well known for becoming brittle and cracking after years of heat cycling. A failure here can quickly lead to overheating, head gasket issues, and major engine damage—bringing any track day or commute to an abrupt end.

Protect your investment with the Mishimoto Performance Aluminum Radiator, engineered specifically for the 2002–2007 Subaru WRX and STI. After identifying the OEM radiator as a weak point, Mishimoto’s engineers designed a durable, high-efficiency replacement built to withstand the demands of spirited driving and competitive environments while providing the reliability you need every day.

This radiator features full aluminum construction for increased heat dissipation, improved pressure tolerance, and long-term durability. Its 100% brazed aluminum core and robust TIG-welded end tanks ensure consistent cooling performance and resistance to failure. As a complete bolt-in upgrade, installation requires no modifications and fits seamlessly in place of the factory unit.

To further enhance cooling efficiency, the Mishimoto Performance Radiator includes two 1.3 bar high-pressure caps—one for the radiator and one for the expansion tank. These caps raise the coolant’s boiling point, increasing the system’s thermal capacity and allowing your Subaru to maintain safe temperatures under aggressive driving. A magnetic drain plug is also included for added protection.

Features:

• Full aluminum construction improves heat and pressure tolerance, cooling efficiency, and long-term durability
• TIG-welded end tanks for maximum strength and reliability
• 100% brazed aluminum core for consistent, efficient cooling
• Increased coolant capacity enhances temperature control during aggressive driving
• Includes two 1.3 bar high-pressure caps to raise coolant boiling point and optimize system performance
• One-way radiator cap and two-way expansion tank cap ensure proper flow and prevent overheating
• Designed to OE specifications for a direct fit on 2002–2007 WRX and 2004–2007 STI
• Magnetic drain plug included

Included:

• Mishimoto Radiator
• Mishimoto Radiator Cap
• 1/16-inch NPT Plug
• Fan Mounting Hardware
• Magnetic Drain Plug

Notes: 

• This item is for Manual Transmission vehicles. For automatic applications, please purchase optional Mishimoto transmission cooler (P/N: MMTC-U)
  
• The provided Mishimoto two way cap (six-sided design) should replace the stock cap located on the expansion tank. The Mishimoto Performance Aluminum Radiator should utilize the included one way cap (circular design with non-directional sticker).