Compatible Honda Civic Si Models

The Mishimoto Performance Aluminum Radiator is compatible with:

• 2006 Honda Civic Si
• 2007 Honda Civic Si
• 2008 Honda Civic Si
• 2009 Honda Civic Si
• 2010 Honda Civic Si
• 2011 Honda Civic Si

Engine compatibility:

• K-series Civic Si models

Perfect for:

• Street builds
• Track cars
• K24-swapped Civics
• Supercharged builds
• Daily-driven Si projects
• Autocross setups

Because no FA5 or FG2 owner keeps the factory airbox forever.

A Mishimoto performance aluminum radiator is the right upgrade to the stock Civic radiator. For a cooler more efficient running engine, all Mishimoto radiators are designed and engineered to maximize cooling and spice up engine purposes.

Improved Cooling Performance

One of the biggest upgrades over the stock radiator is:

• Improved heat dissipation
• Better thermal stability
• Reduced heat soak
• More consistent coolant temperatures

Especially beneficial during:

• High-RPM driving
• Track sessions
• Summer traffic
• Canyon runs
• Aggressive daily driving

Where stock cooling systems occasionally begin emotionally overheating.

Overall Size: 26.8 x 18.2 x 2.07 inches. Includes a two-row, 1.57 inch thick brazed aluminum core which gives efficient fluid temperature regulation in the street and track

Two-Row Brazed Aluminum Core

The Mishimoto radiator features:

• Fully brazed aluminum construction
• Two-row cooling core
• 1.57-inch thick core design

Specifications:

• Overall size: 26.8” x 18.2” x 2.07”
• Inlet/outlet size: 1.25”
• Core thickness: 1.57”
• Tank wall thickness: 0.08”

This improves:

• Heat transfer efficiency
• Cooling consistency
• Thermal recovery
• Long-session durability

Especially important because K-series engines treat redline like a mandatory personality trait.

Inlet & Outlet: 1.25 inch / Core Thickness: 1.57 inch / Tank Wall Thickness: 0.08 inch

Full Aluminum Construction Benefits

Unlike factory radiators that commonly use:

• Plastic end tanks
• Aging crimp seams
• OEM composite materials

The Mishimoto radiator uses:

• Welded aluminum tanks
• Reinforced aluminum construction
• Performance-grade cooling materials

Helping improve:

• Durability
• Pressure resistance
• Long-term reliability
• Cooling system longevity

Because old Honda plastic radiator tanks eventually crack with the predictability of sunrise.

All-aluminum construction contains magnetic drain plug
Mishimoto Lifetime Guaranty

Perfect for Track & Autocross Builds

This radiator is especially valuable for:

• HPDE track cars
• Time attack builds
• Autocross Civics
• K24 swap projects
• Supercharged K-series setups

Improved cooling helps reduce:

• Heat soak
• Coolant spikes
• Thermal fatigue
• Power loss during long sessions

Especially because naturally aspirated Hondas somehow generate track heat levels completely disproportionate to their displacement.

Better Cooling for Modified K-Series Engines

This radiator is ideal for:

• FlashPro-tuned setups
• RBC manifold builds
• Header-equipped Si models
• High-compression engines
• Aggressive street cars

Improved cooling helps maintain:

• Stable operating temperatures
• Better power consistency
• Reduced thermal stress
• Improved engine reliability

Because VTEC plus aggressive tuning eventually turns engine bays into thermal management exercises.

OEM-Style Direct Fit Installation

The radiator is engineered for:

• Direct bolt-in installation
• OEM hose compatibility
• Factory mounting integration

Typical installation requires:

• Coolant drain
• Socket set
• Hose clamp pliers
• Approximately 1-3 hours

No major:

• Fabrication
• Cutting
• Custom mounting typically required

Which is fortunate, because eighth-gen Civic engine bays already become crowded immediately after modifications begin.

Why Upgrade the Civic Si Radiator?

Common reasons Civic Si owners upgrade radiators include:

• Track overheating concerns
• Heat soak reduction
• Preventative maintenance
• Supercharger cooling demands
• K24 swap reliability
• High-mileage cooling upgrades

A performance radiator remains one of the smartest upgrades for K-series Hondas because:

• Heat kills consistency quickly
• Track driving exposes cooling limitations fast
• Modified K-series engines create significant thermal load

Especially once VTEC engagement becomes a daily event.

Final Verdict

For 2006-2011 Honda Civic Si owners wanting improved cooling performance and long-term reliability, the Mishimoto Performance Aluminum Radiator delivers serious thermal management upgrades with track-capable cooling efficiency.

Key benefits include:

• Fully aluminum construction
• Two-row brazed core
• Improved heat dissipation
• Better thermal stability
• Ideal for track and K-series builds
• Direct-fit installation

Most importantly, your Civic Si finally stops treating every VTEC pull like a coolant temperature stress test.