Mishimoto MMRAD-WRX-01 Aluminum Radiator 2001-2007 Subaru WRX STI GD EJ Manual

Vehicle Fitment

• 2001-2007 Subaru WRX (GD Chassis, EJ205 2.0L Turbo H4, Manual Transmission, AWD)
• 2004-2007 Subaru STI (GD Chassis, EJ257 2.5L Turbo H4, Manual Transmission, AWD)
• 2005 Saab 9-2X (GD-based platform, H4 2.0L, Manual Transmission, AWD)

Fitment Notes

• Manual transmission only. This radiator does not include an integrated automatic transmission fluid cooler. Owners of automatic transmission WRX or STI models must source a separate transmission cooler - Mishimoto's Universal Transmission Cooler Kit is a compatible option.
• Critical dual-cap installation caution - GD WRX/STI: The GD-chassis Subaru WRX and STI uses two separate radiator caps in the cooling system. This kit now ships with both caps required for proper operation. The two-way cap (six-sided design) must be installed on the expansion tank. The one-way cap (circular design with non-directional sticker) must be installed on the radiator neck. Installing the caps in reversed positions will cause overheating. Do not install the one-way radiator cap on the expansion tank or the two-way expansion tank cap on the radiator.
• Radiator style: Downflow. Inlet and outlet are both 1.5 in. Drain plug thread: M12 x 1.5.
• Engine codes: EJ205 (WRX), EJ255 (Legacy GT / Forester XT), EJ257 (STI). Chassis code: GD.
• Installation difficulty rated Medium. An official Mishimoto installation guide (PDF) is available for download.

Features

• Direct OEM-fit performance aluminum radiator engineered specifically for the 2001-2007 Subaru WRX and STI on the GD chassis - identified by Mishimoto's engineers as a platform where the factory plastic-tank radiator is a documented weak point, particularly prone to end-tank cracking from repeated thermal cycling under the aggressive temperature variation inherent to turbocharged AWD driving and track use.
• Full aluminum construction with TIG-welded end tanks - eliminates the plastic end-tank cracking failure mode entirely. Aluminum provides increased heat and pressure tolerance, improved heat dissipation, and improved cooling efficiency versus the OEM plastic-tank/aluminum-core construction.
• 100% brazed aluminum two-row core (27.24" x 13.54" x 1.65" thick) provides a significant increase in coolant capacity (2.3 gal) and heat transfer surface area, delivering meaningful temperature reductions during track lapping, rallycross, hill climb, and sustained aggressive street driving - all conditions where the OEM WRX/STI radiator is known to be stressed.
• A radiator failure on an EJ-powered Subaru carries elevated risk: head gasket failure - already an EJ engine concern - is accelerated by coolant temperature excursions, making a robust cooling system particularly important for the long-term reliability of this platform.
• Includes two 1.3 bar high-pressure radiator caps matched to the GD WRX/STI dual-cap cooling architecture: one two-way cap (for the expansion tank) and one one-way cap (for the radiator). Each is distinctly designed to prevent installation errors - see fitment notes for cap placement details.
• Includes a magnetic drain plug (M12 x 1.5) to capture ferrous metallic particles circulating in the coolant, protecting the water pump and core from debris-related wear.
• Complete bolt-in installation with no chassis modification, cutting, or drilling required. Fan mounting hardware and 1/16" NPT plug included.
• DPI: 2703. Backed by the Mishimoto Lifetime Warranty.

Specifications

• Overall Dimensions: 28.4 in (H) x 17.2 in (L) x 2.15 in (W)
• Core Dimensions: 27.24 in x 13.54 in x 1.65 in thick
• Rows: 2
• Radiator Style: Downflow
• Inlet: 1.5 in / Outlet: 1.5 in
• Coolant Capacity: 2.3 gal
• Drain Plug Thread: M12 x 1.5
• DPI: 2703
• Engine Codes: EJ205, EJ255, EJ257
• Chassis Code: GD
• Transmission Cooler: Not included

Included Components

• 1x Mishimoto performance aluminum radiator
• 1x 1.3 bar one-way radiator cap (circular, for radiator neck - Subaru-specific)
• 1x 1.3 bar two-way expansion tank cap (six-sided, for expansion tank)
• 1x Magnetic drain plug (M12 x 1.5)
• 1x 1/16" NPT plug
• Fan mounting hardware
• Mishimoto Lifetime Warranty

Product Description

The Mishimoto MMRAD-WRX-01 is a direct OEM-fit performance aluminum radiator engineered for the 2001-2007 Subaru WRX and STI on the GD chassis with manual transmission. The GD WRX and STI are among the most enthusiast-driven platforms Subaru has produced - the EJ-powered AWD turbocharged combination made these cars genuine all-conditions performance vehicles, competitive in rally, track, autocross, and rallycross as well as daily driving. The cooling system, however, is a well-documented liability. The factory radiator's plastic end tanks develop fatigue cracks from the repeated and rapid temperature cycling characteristic of turbocharged operation, and when they fail - especially on a track day or during aggressive driving - the consequences can include overheating, and on the EJ engine, accelerated head gasket failure is a known downstream risk from coolant temperature excursions.

Mishimoto's replacement eliminates the plastic end-tank failure mode with a full aluminum TIG-welded construction bonded to a 100% brazed two-row core that provides a substantial increase in coolant capacity to 2.3 gallons. The aluminum construction provides improved heat and pressure tolerance, better heat dissipation, and greater structural durability than the OEM unit across the full range of operating conditions these cars encounter. The radiator installs as a direct bolt-in replacement on the GD chassis with no modifications required.

A critical installation detail specific to the GD WRX and STI: the cooling system uses two separate radiator caps, each with different directional flow characteristics. This kit ships with both - a two-way cap (six-sided) for the expansion tank and a one-way cap (circular with non-directional sticker) for the radiator neck. These must not be swapped; incorrect cap placement will cause overheating. Fan mounting hardware, a 1/16" NPT plug, and a magnetic drain plug are also included. Also fits the 2005 Saab 9-2X, which shared the GD platform. For maximum cooling performance, pairs with the Mishimoto WRX/STI X-Line radiator (MMRAD-WRX-01X), silicone hose kit, and performance thermostat. Covered by the Mishimoto Lifetime Warranty.