Koyo Aluminum Radiator for 02-06 Acura RSX

Koyo Aluminum Radiator - 2002-2006 Acura RSX (Manual Transmission)

Your RSX's radiator's been in there for 15-20 years. The plastic end tanks are brittle. The core's clogged with scale and corrosion. You're watching the temp gauge climb when you're sitting in traffic or when you're pushing it hard. The plastic's going to crack. Probably when you're on the highway in the summer. Koyo's all-aluminum radiator replaces the entire stock plastic-tank setup with a hand-TIG-welded aluminum unit. No plastic end tanks to fail. No crimped seams to leak. Just hand-welded aluminum tanks and a Nocolok-brazed core that's built to handle way more heat than the stock radiator ever could. The radiator's designed to OE specifications so it bolts right into your RSX using the stock fan shroud and stock hoses. Direct bolt-in. Two hours to install. Koyo's Japan's largest aftermarket radiator manufacturer and they're hand-assembling these in their own factories with triple pressure testing. The finish is mirror-polished. This isn't a cheap eBay radiator with rough welds and a rattle-can paint job. This is a Koyo.

Here's Why Your Stock RSX Radiator's Already Failing

The stock RSX radiator uses an aluminum core with plastic end tanks crimped to the sides. The plastic's the weak point. After 15-20 years of heat cycling, it's brittle. The tanks crack around the filler neck or the inlet/outlet connections. The crimped seams start weeping coolant. We've seen RSX radiators with hairline cracks in the plastic that the owner didn't know were there until they checked the coolant level and it was a quart low. The crack opens all the way one day and you're stranded with coolant pouring out and the temp gauge buried in the red. The core's also probably half-clogged because nobody's flushed their coolant in 10 years. Rust, scale, and sediment are blocking half the tubes. Your radiator's trying to cool but it can't flow coolant through tubes that are packed with corrosion. Koyo's radiator is all aluminum. Hand-TIG-welded end tanks so there's no crimped seam to leak. Nocolok-brazed core with precise tube and fin alignment so every tube's flowing and every fin's transferring heat. You're getting 20-30% more cooling capacity than the stock radiator. That's not marketing hype. That's actual heat transfer improvement from more core surface area and better construction.

Built for High-Performance K Series Engines

Koyo builds this radiator to handle K series engines making way more power than stock. If you're running a turbocharged K20, a supercharged K24, or you're spraying nitrous, this radiator's designed for that. High-revving engines making serious power generate way more heat than stock engines. The stock radiator can barely keep up with a bone-stock RSX in traffic. It's not going to handle a K20 making 400 whp on a hot day. Koyo's radiator is built with thicker cores and more fin density than the stock radiator. The core's Nocolok-brazed which is vacuum brazing where the aluminum's heated in a controlled atmosphere and the joints are fused without solder or epoxy. It's stronger and more uniform than traditional soldering. The tubes aren't going to separate. The fins aren't going to fall off when you're making boost. Koyo hand-assembles every core and then hand-TIG-welds the aluminum end tanks. Each radiator's triple pressure-tested before it ships. They're not sending out radiators that leak. This is the same quality control that made Koyo the OEM supplier for half the Japanese car companies.

You Need a Radiator Cap - Stock Cap Won't Fit

The stock RSX radiator cap doesn't fit this radiator. The filler neck's a different design. You need a Koyo, SpeedFactory Type A, or Hybrid Racing Type F radiator cap. That's sold separately. Don't try to use your stock cap. It won't seal. You'll have pressure loss and coolant burping out the overflow. Buy the cap when you buy the radiator. The Koyo SK-C13 is the cap that fits this radiator. That's a 1.3 bar (18.85 PSI) high-pressure cap. Higher pressure raises the boiling point of your coolant from around 250°F to around 257°F. That extra headroom matters when you're running hard or sitting in traffic on a 95°F day with the A/C blasting.

Direct Bolt-In with Stock Fan Shroud and Hoses

This radiator's a direct OE replacement. Same mounting points as the stock radiator. Same hose connections. Your stock fan shroud bolts right up. Your stock upper and lower radiator hoses connect. All your sensors and switches mount in the factory locations. You're pulling the old radiator and bolting this one in. No cutting. No drilling. No custom brackets. Installation's straightforward if you've done cooling system work before. Drain the old coolant, unbolt the old radiator, bolt in the Koyo, connect your hoses and fan shroud, fill it with fresh coolant, burp the air out, and you're done. Two hours tops. The radiator comes with a mirror-polished finish. It doesn't look like a cheap aftermarket radiator with rough welds and overspray. It looks like a piece you'd expect to see on a clean build. Koyo builds these radiators to OE specifications which means they're designed as direct replacements. Everything bolts up exactly like the factory radiator did.

What You Get

• Koyo all-aluminum radiator for 2002-2006 RSX (manual transmission only)
• Hand-TIG-welded aluminum end tanks (no plastic to crack)
• Nocolok-brazed core (vacuum brazed, no solder or epoxy)
• 20-30% more cooling capacity than stock radiator
• Built for high-performance turbocharged, supercharged, and nitrous engines
• Precise tube and fin alignment (every tube flows, every fin transfers heat)
• Mirror-polished finish (no rough welds or overspray)
• Triple pressure-tested at Koyo factory in Japan
• Direct OE replacement (stock fan shroud, stock hoses, stock mounting points)
• Aircraft-quality aluminum construction
• Made by Koyo in Japan

Fits These Cars

• 2002-2006 Acura RSX Base (manual transmission only, K20A3 engine)
• 2002-2006 Acura RSX Type-S (manual transmission only, K20A2/K20Z1 engine)

Note: Manual transmission only - automatic cars use different radiator. Stock radiator cap does NOT fit - must use Koyo radiator cap (sold separately, Koyo SK-C13 recommended, 1.3 bar high-pressure). All-aluminum construction eliminates plastic end tank failures (stock has plastic tanks that crack after 15-20 years). Hand-TIG-welded aluminum end tanks and Nocolok-brazed core (no crimped seams, no solder, no epoxy). 20-30% more cooling capacity than stock radiator (actual heat transfer improvement from more core surface area and better construction). Designed for high-performance turbocharged, supercharged, and nitrous K series engines. Aircraft-quality aluminum construction with Heli-arc welding (highest quality standard for aluminum connections). Direct OE replacement using stock fan shroud, stock upper and lower hoses, stock sensors and switches. Same mounting points as stock radiator (no cutting, no drilling, no custom brackets). Mirror-polished finish. Triple pressure-tested at Koyo factory in Japan. Made by Koyo - Japan's largest aftermarket radiator manufacturer and OEM supplier. Fits 2002-2006 RSX Base and Type-S with manual transmission. Installation takes 2 hours (drain coolant, unbolt old radiator, bolt in Koyo, connect hoses and fan shroud,