Authorized Brand Dealer
Fulfillment From Multiple U.S. Warehouses
Enthusiast Owned & Supported
Easy Financing Available!
Authorized Brand Dealer
Fulfillment From Multiple U.S. Warehouses
Enthusiast Owned & Supported
Easy Financing Available!
Authorized Brand Dealer
Fulfillment From Multiple U.S. Warehouses
Enthusiast Owned & Supported
Easy Financing Available!
Authorized Brand Dealer
Fulfillment From Multiple U.S. Warehouses
Enthusiast Owned & Supported
Easy Financing Available!
Authorized Brand Dealer
Fulfillment From Multiple U.S. Warehouses
Enthusiast Owned & Supported
Easy Financing Available!
Authorized Brand Dealer
Fulfillment From Multiple U.S. Warehouses
Enthusiast Owned & Supported
Easy Financing Available!
Welcome to Atlus Automotive
Main menu
-
Performance
- Performance
-
Air Intake
-
Exhaust
-
Engine
-
Turbo & Cooling
-
Fuel, Ignition & Tuning
-
Suspension
- Suspension
-
Coilovers & Lowering
-
Lift & Off-Road
-
Arms, Bushings & Alignment
-
Sway Bars & Chassis
-
Brakes
- Brakes
-
Pads & Rotors
-
Kits, Calipers & Lines
-
Top Brake Brands
-
Wheels & Tires
- Wheels & Tires
-
Wheels & Tires
-
Drivetrain & Clutch
-
Exterior & Lighting
- Exterior & Lighting
-
Lighting
-
Body & Styling
-
Bumpers & Protection
-
Interior & Electronics
- Interior & Electronics
-
Interior
-
Gauges & Data
-
Audio, Power & Wiring
-
Overland & Utility
-
Maintenance & Garage
- Maintenance & Garage
-
Oils, Fluids & Car Care
-
Fabrication & Tools
Your cart
-
0 – 9
-
R
-
S
Mishimoto
Mishimoto 12-15 Honda Civic Si Performance Radiator
This product will be available for sale in 2 weeks, but you can pre-order now to receive 10% discount!
Upgrade the cooling system of your 2012-2015 Honda Civic Si with this Mishimoto Performance Aluminum Radiator, built to manage the sustained thermal output of a high-revving K-series engine on the street and the track. All-aluminum construction with precision TIG-welded end tanks outlasts the factory plastic-tanked unit prone to cracking under heat cycling and repeated high-rpm use. A 63% increase in core volume over the OEM radiator delivers greater surface area and thermal capacity, keeping coolant temperatures stable during back-to-back pulls, spirited street sessions, and weekend track days where the stock radiator starts to fall behind.----Designed as a direct-fit replacement for the 2012-2015 Honda Civic Si, this radiator drops in without cutting, fabricating, or modifications, and works seamlessly with all stock hoses and components without alteration. The included high-pressure radiator cap maintains optimal system pressure from the first drive, extracting the full benefit of the upgraded core. The Mishimoto Magnetic Drain Plug catches ferrous metallic debris before it circulates through the cooling system, protecting your K-series engine internals and extending service life beyond what the factory setup allows.----Don't wait for your stock radiator to crack and leave you sidelined. Whether you daily drive your Civic Si, push it hard on weekend canyon runs, or are building toward a higher-output K-series setup, this aluminum radiator handles the sustained thermal demands your factory unit was never built for. Proactive cooling upgrades protect your engine investment - and this one is built to outlast it. Backed by the Mishimoto Lifetime Warranty, this Performance Aluminum Radiator is the last cooling upgrade your 2012-2015 Honda Civic Si will ever need.
Installation Instructions- Built for the high-rev demands of the Civic Si K-series — the oversized aluminum core absorbs sustained thermal output during back-to-back pulls, spirited street driving, and track sessions where the stock radiator begins to fall behind.
- Magnetic drain plug removes ferrous debris before it circulates — catches metallic particles from the cooling system to protect K-series engine internals and extend service life beyond the stock interval.
- All-aluminum construction, no plastic to crack — full aluminum end tanks joined by precision TIG-welds replace the factory components that fail under heat cycling and sustained high-rpm use.
- 63% more core volume over stock — the enlarged core delivers greater surface area and thermal capacity than the factory unit, running measurably cooler when the K-series is pushed hardest.
- Drops in without modification — confirmed direct fit for the 2012-2015 Honda Civic Si, compatible with all stock hoses and components — no cutting, fabricating, or adapter work required.
- Included high-pressure radiator cap maintains optimal system pressure — delivers enhanced cooling performance from the first drive without sourcing additional components.
- Own it for life — backed by Mishimoto's Lifetime Warranty, your investment is protected long after install day.
This Part Fits:
| Year | Make | Model | Submodel |
|---|---|---|---|
| 2012-2015 | Honda | Civic | Si |
Choose your Location
-
Atlus
1340 Cobb Dr, Unit 1, Eustis, FL 32736
352-234-4458
Mon – Fri: 8:30 am – 4:30 pm
Sat: 9:00 am – 2:00 pm
Sun: Closed
Product Comparison
How they are Different
|
__ __ |
|
|---|---|
| Description |
Description - __ |
| Rating |
Rating - __ |
| Vendor |
Vendor - __ |
| Color |
Color - __ |
|
|
Compare products ( / )
The Atlus Price Guarantee
If you can find the part for a lower price from an authorized dealer/shop, we'll match the price! Reach out to Hello@AtlusAuto.com, our live chat located at the bottom right of your screen, or request an Atlas Price Guarantee, or visit our dedicated APG page to submit a request.
Mishimoto 12-15 Honda Civic Si Performance Radiator
This product will be available soon, but you can pre-order now to get on the list before others!
US Based Support - In Florida
30 Days Satisfaction Guarantee
Price Match
If you can find the part for a lower price from an authorized dealer/shop, we'll match the price! Reach out to Hello@AtlusAuto.com, our live chat located at the bottom of your screen, or request an Atlas Price Guarantee, or visit our dedicated APG page to submit a request.
Easy Financing
We've partnered up with Affirm/Shop!
Why use Affirm/Shop?
- Clear application process
- Friendly support team
- Spread a big payment interest-free
- Ability to buy what you want
How does it work?
- Add your purchase to cart
- Select Shop Payments at checkout
- Complete the application
- Compare any available finance options
Share:
Upgrade the cooling system of your 2012-2015 Honda Civic Si with this Mishimoto Performance Aluminum Radiator, built to manage the sustained thermal output of a high-revving K-series engine on the street and the track. All-aluminum construction with precision TIG-welded end tanks outlasts the factory plastic-tanked unit prone to cracking under heat cycling and repeated high-rpm use. A 63% increase in core volume over the OEM radiator delivers greater surface area and thermal capacity, keeping coolant temperatures stable during back-to-back pulls, spirited street sessions, and weekend track days where the stock radiator starts to fall behind.----Designed as a direct-fit replacement for the 2012-2015 Honda Civic Si, this radiator drops in without cutting, fabricating, or modifications, and works seamlessly with all stock hoses and components without alteration. The included high-pressure radiator cap maintains optimal system pressure from the first drive, extracting the full benefit of the upgraded core. The Mishimoto Magnetic Drain Plug catches ferrous metallic debris before it circulates through the cooling system, protecting your K-series engine internals and extending service life beyond what the factory setup allows.----Don't wait for your stock radiator to crack and leave you sidelined. Whether you daily drive your Civic Si, push it hard on weekend canyon runs, or are building toward a higher-output K-series setup, this aluminum radiator handles the sustained thermal demands your factory unit was never built for. Proactive cooling upgrades protect your engine investment - and this one is built to outlast it. Backed by the Mishimoto Lifetime Warranty, this Performance Aluminum Radiator is the last cooling upgrade your 2012-2015 Honda Civic Si will ever need.
Installation Instructions- Built for the high-rev demands of the Civic Si K-series — the oversized aluminum core absorbs sustained thermal output during back-to-back pulls, spirited street driving, and track sessions where the stock radiator begins to fall behind.
- Magnetic drain plug removes ferrous debris before it circulates — catches metallic particles from the cooling system to protect K-series engine internals and extend service life beyond the stock interval.
- All-aluminum construction, no plastic to crack — full aluminum end tanks joined by precision TIG-welds replace the factory components that fail under heat cycling and sustained high-rpm use.
- 63% more core volume over stock — the enlarged core delivers greater surface area and thermal capacity than the factory unit, running measurably cooler when the K-series is pushed hardest.
- Drops in without modification — confirmed direct fit for the 2012-2015 Honda Civic Si, compatible with all stock hoses and components — no cutting, fabricating, or adapter work required.
- Included high-pressure radiator cap maintains optimal system pressure — delivers enhanced cooling performance from the first drive without sourcing additional components.
- Own it for life — backed by Mishimoto's Lifetime Warranty, your investment is protected long after install day.
This Part Fits:
| Year | Make | Model | Submodel |
|---|---|---|---|
| 2012-2015 | Honda | Civic | Si |
Authencity Guaranteed
We only sell authentic products from verified brand partners and retail partners globally.
Can’t Find the Part You Need?
Our catalog represents only a portion of the automotive products available through our supplier network. If you cannot find a specific part, brand, or application on our website, submit a request below, and our team will help source it for you.
Please include as much information as possible, such as your vehicle's year, make, model, trim, engine, desired brand, or part number, to help us quickly identify the correct product.
- Choosing a selection results in a full page refresh.
- Opens in a new window.