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.