Vehicle Fitment

The Mishimoto MMRAD-STI-08 is designed for:

Subaru WRX

• 2008 Subaru WRX
• 2009 Subaru WRX
• 2010 Subaru WRX
• 2011 Subaru WRX
• 2012 Subaru WRX
• 2013 Subaru WRX
• 2014 Subaru WRX

Subaru STI

• 2008 Subaru STI
• 2009 Subaru STI
• 2010 Subaru STI
• 2011 Subaru STI
• 2012 Subaru STI
• 2013 Subaru STI
• 2014 Subaru STI
• 2015 Subaru STI
• 2016 Subaru STI
• 2017 Subaru STI
• 2018 Subaru STI
• 2019 Subaru STI

Always verify fitment before ordering.

Mishimoto Radiator Specifications

The MMRAD-STI-08 features:

• Overall Dimensions: 28″ x 21.8″ x 2.15″
• Core Size: 13.39″ x 27.08″
• Two-Row Aluminum Core
• Core Thickness: 1.65″
• Inlet Diameter: 1.54″
• Outlet Diameter: 1.54″
• Tank Wall Thickness: 0.08″
• TIG-Welded Aluminum Construction
• High-Pressure Radiator Cap Included
• Magnetic Drain Plug Included

These features combine to create a cooling system upgrade designed for both performance and durability.

Up to 30 Percent Better Cooling Efficiency

One of the biggest selling points of the Mishimoto radiator is its increased cooling capacity.

According to Mishimoto, this radiator is engineered to improve cooling efficiency by up to 30 percent compared to factory cooling systems.

Benefits may include:

• Lower coolant temperatures
• Reduced risk of overheating
• Improved consistency during track sessions
• Better cooling under boost
• Enhanced engine protection

For turbocharged Subaru applications, every degree of temperature control matters.

Fully Aluminum Construction

Unlike factory radiators that use plastic end tanks, the Mishimoto unit utilizes all-aluminum construction.

Advantages include:

Improved Strength

Aluminum tanks are significantly more resistant to cracking and fatigue compared to aging plastic components.

Better Heat Transfer

Aluminum dissipates heat efficiently, helping maximize cooling performance.

Long-Term Reliability

Many Subaru owners upgrade before factory radiator failure becomes an issue, preventing costly overheating events.

TIG-Welded Construction

The radiator features fully TIG-welded aluminum tanks and core sections.

Benefits include:

• Stronger weld integrity
• Improved durability
• Better resistance to pressure cycles
• Professional motorsports-style construction

This level of manufacturing quality is one reason Mishimoto products have become so popular in the performance market.

Included High-Pressure Radiator Cap

The included high-pressure radiator cap helps maintain proper system pressure.

Advantages include:

• Improved boiling point protection
• Enhanced cooling system performance
• Additional value included with the radiator

It’s a small detail that can make a noticeable difference in cooling efficiency.

Magnetic Drain Plug

Mishimoto also includes a magnetic drain plug.

This feature helps capture metallic debris that may circulate through the cooling system, providing an additional layer of protection and making maintenance inspections easier.

Ideal for Modified Subarus

The MMRAD-STI-08 is especially beneficial for:

• Tuned WRXs
• Modified STIs
• Track cars
• Autocross vehicles
• Canyon cars
• Daily drivers in hot climates

Supporting modifications often include:

• Upgraded intercoolers
• Larger turbochargers
• Performance tuning
• Oil coolers
• High-performance cooling fans

Installation

The Mishimoto radiator is designed as a direct-fit replacement for factory units.

Installation typically requires:

• Coolant drain and refill
• Removal of factory radiator
• Transfer of cooling components as necessary
• System bleeding

No major modifications are typically required.

Mishimoto Lifetime Warranty

One of the strongest selling points of this radiator is Mishimoto’s lifetime warranty coverage.

This warranty demonstrates confidence in the product’s durability and provides additional peace of mind for enthusiasts investing in their vehicle’s cooling system.

Final Verdict

The Mishimoto MMRAD-STI-08 Performance Aluminum Radiator is one of the most worthwhile cooling upgrades available for the 2008-2014 Subaru WRX and 2008-2019 Subaru STI. With improved cooling capacity, all-aluminum construction, TIG-welded durability, and a lifetime warranty, it offers a substantial improvement over the factory radiator.

Whether you’re building a track-focused STI, adding horsepower to your WRX, or simply replacing an aging factory radiator before it fails, the Mishimoto MMRAD-STI-08 delivers the cooling performance and reliability Subaru enthusiasts demand.