Mishimoto Performance Aluminium Radiator – 2012–2015 Honda Civic Si | MMRAD-CIV-12SI

Mishimoto MMRAD-CIV-12SI performance aluminium radiator for the 2012–2015 Honda Civic Si (FB6, K24Z7). 63% increase in core volume over the OEM radiator, all-aluminium TIG-welded construction, direct-fit replacement. Includes high-pressure radiator cap and magnetic drain plug. Backed by Mishimoto’s Lifetime Warranty. 13.4 lbs. Ships fast across Canada and the US.

63% Core Volume Increase

The factory Civic Si radiator uses a plastic-tanked aluminium core construction that degrades over time — the plastic end tanks become brittle under repeated heat cycling and are prone to cracking, particularly on high-revving K-series engines subjected to sustained track or spirited street use. Mishimoto’s radiator replaces this with a fully aluminium unit featuring precision TIG-welded end tanks and a core 63% larger in volume than OEM. The increased core surface area and thermal capacity keeps coolant temperatures stable through back-to-back pulls and extended high-load sessions where the stock radiator falls behind.

Direct-Fit Replacement

Designed as a direct-fit replacement for the 2012–2015 Civic Si — drops in using all factory mounting points, hose connections, and hardware without cutting, fabricating, or modification. Stock hoses and cooling system components connect without alteration.

Included Components

• High-pressure radiator cap — maintains optimal system pressure from installation
• Magnetic drain plug — captures ferrous metallic debris before it circulates through the cooling system, protecting K-series engine internals

Mishimoto Lifetime Warranty

Covered by Mishimoto’s Lifetime Warranty against defects in materials and workmanship for the original purchaser.

Fitment

• 2012–2015 Honda Civic Si — FB6 — K24Z7 2.4L

Drain and flush the cooling system before installation. Bleed the cooling system thoroughly after installation to eliminate air pockets. Torque all hose clamps and fittings to specification. Register Mishimoto Lifetime Warranty through Mishimoto directly after installation.

Specifications

• Brand: Mishimoto
• Part Number: MMRAD-CIV-12SI
• Construction: All-aluminium, TIG-welded end tanks
• Core Volume: 63% increase over OEM
• Fit: Direct-fit replacement
• Includes: High-pressure cap, magnetic drain plug
• Warranty: Mishimoto Lifetime Warranty
• Weight: 13.4 lbs
• Application: 2012–2015 Honda Civic Si FB6 — K24Z7