TEGIWA Silicone Hose Kit. Silicone hoses can operate under higher temperatures and pressures than OEM rubber hoses and are far less likely to perish too. So if your K-Series block is running increased power, this direct replacement, two-piece silicone coolant hose kit comes highly recommend. They brighten up your engine bay too and are available in blue, red & black. These will only fit FN2 Type R K20Z engines.