PRODUCT DETAILS
Radium Coolant Expansion Tank - FK8/FL5 Type R / Integra Type S
A known weak point on the Type R and Type S is the plastic coolant overflow tank. With too much heat, it can develop cracks that require you to replace the unit. The Radium coolant expansion tank's a direct replacement for the OEM plastic tank. It's CNC-machined from billet aluminum so it's not going to crack or fail from heat cycles like the plastic tank eventually will. The aluminum construction also transfers heat better than plastic so your coolant's shedding heat more efficiently. This kit's a bolt-in replacement - same internal volume as stock, same mounting location, no permanent modifications to your car. It comes with everything you need: aluminum mounting bracket, adapter fittings for the factory coolant lines, heater hose, overflow hose, and stainless hardware. The tank uses your factory radiator cap or any direct replacement cap. If you're tracking your car, running it hard on the street, or you just don't want to deal with a cracked plastic coolant tank down the road, this is the upgrade.
Here's Why the Plastic Tank's Going to Fail
The factory coolant expansion tank's made from plastic. Plastic works fine when it's new but it doesn't age well under constant heat cycles. Every time your engine heats up and cools down, the plastic expands and contracts. After thousands of heat cycles - track days, spirited driving, sitting in traffic - the plastic gets brittle. Eventually it cracks. Usually it's at a seam or around a mounting point. Now you're leaking coolant and you're either overheating or you're stuck on the side of the road waiting for it to cool down so you can limp home. The Radium aluminum tank doesn't have that problem. Aluminum doesn't get brittle from heat cycles. It expands and contracts but it doesn't crack. You're not replacing this tank in five years because it failed.
Better Heat Transfer Than Plastic
Aluminum conducts heat way better than plastic. The coolant in your expansion tank's hot - it's coming from your engine and radiator. The plastic OEM tank insulates that heat. It doesn't shed it efficiently. The aluminum Radium tank acts like a heat sink. It pulls heat out of the coolant and dissipates it into the airflow under your hood. Your coolant's staying cooler in the tank which means your whole cooling system's running more efficiently. It's not a massive difference but when you're running hard on a track or sitting in stop-and-go traffic on a hot day, every bit of cooling efficiency helps.
Direct Bolt-In Replacement
This isn't some custom fab job where you're cutting and welding. The Radium tank's designed to bolt directly into the factory location using the included aluminum mounting bracket. It's got the same internal volume as the stock tank so you're not changing your coolant capacity. The kit comes with adapter fittings that connect to your factory coolant lines - you're not hunting for custom fittings or modifying your hard lines. The heater hose and overflow hose are included and they're the right lengths to connect everything up. The whole install's reversible. If you sell the car or go back to stock for some reason, you can unbolt the Radium tank and reinstall the factory tank. Your car's not permanently modified.
What You Get
- Radium coolant expansion tank - CNC-machined billet aluminum
- Aluminum mounting bracket
- Aluminum adapter fittings for factory coolant lines
- Heater hose (5/16")
- Overflow hose (7/32")
- Stainless steel hardware
- Anodized finish for corrosion resistance
- Same internal volume as OEM tank
- Direct bolt-in installation - no permanent modifications
- Uses factory radiator cap or direct replacement
Fits Your Car
- 2017-2021 Honda Civic Type R (FK8)
- 2023-2026 Honda Civic Type R (FL5)
- 2024-2026 Acura Integra Type S
Note: Radiator cap is NOT included. Reuse your factory radiator cap or install a direct replacement cap. The factory cap works fine. This tank holds the same amount of coolant as the factory tank so your coolant capacity doesn't change. When you're installing the tank, replace your coolant with fresh coolant. Don't reuse old coolant that's been sitting in your system for years. Burp the cooling system after you've installed the tank and filled it, run the engine with the radiator cap off until the thermostat opens and you're not seeing air bubbles coming up. Top off the coolant and reinstall the cap. Check for leaks at all the hose connections after the first heat cycle. The anodized finish on the aluminum will show fingerprints and smudges so if you want it looking clean, wipe it down with a microfiber cloth after you install it.