Koyorad Performance Radiator for Lexus IS250 / IS350 GSE20 / GSE21 / GSE25 2005+
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Description
Koyo Performance Radiator – Lexus IS250 / IS350 GSE20 / GSE21 / GSE25 2005+
Application: Lexus IS250 / IS350 | DBA-GSE20 / DBA-GSE21 / DBA-GSE25 | 4GR-FSE / 2GR-FSE | 2005+
Part Numbers: KH011937 (Koyorad) / KH011937 (iilumolab)
The Lexus IS250 and IS350 represent the sharp end of Toyota's rear-wheel-drive performance sedan lineup — refined, capable machines that are increasingly popular as track and street performance builds. The 4GR-FSE and 2GR-FSE engines are smooth, high-revving units that benefit from improved thermal management, particularly under sustained high-load driving conditions.
Koyorad's all-aluminium KH011937 is a direct bolt-in performance upgrade engineered specifically for the GSE20-series IS platform. Nocolok furnace brazed, precision TIG welded by hand, and triple pressure tested — it retains all OEM fan shroud mounts and stock hose connections with no modifications required.
Why Koyorad?
- Precise Tube & Fin Alignment — Strict quality control ensures optimal coolant flow and maximum heat transfer efficiency across the entire core.
- Nocolok Furnace Brazing — All tubes, fins, headers, and brackets are bonded in a state-of-the-art Nocolok furnace, creating a structure that resists vibration, road debris, and the elements.
- Billet Filler Neck — Precision-machined billet filler necks are fitted to every unit for superior strength, durability, and a reliable seal.
- OE-Specific Mounting — Application-specific mounting points for fan shrouds, inlet/outlet hoses, and top/bottom pins ensure a pain-free, no-modification install.
- Hand-Crafted Heliarc Welds — Each radiator is individually Heliarc welded by hand, creating the strongest possible aluminium-to-aluminium bond across all components.
Specifications
| Part Number | KH011937 |
| Core Thickness | 48mm |
| Core Dimensions (H × W) | 375 × 704/728mm |
| Tank Dimensions | 55/55 × 735mm |
| Inlet / Outlet Diameter | TBA |
| Construction | All Aluminium, Nocolok Brazed, Heliarc Welded |
| Fan Shroud | Retains OEM mounts |
| Hoses | Compatible with stock radiator hoses |
| Fitment | Direct bolt-in, no modifications required |
Cross Reference
| Koyorad | KH011937 |
| Lexus / Toyota OEM | 16400 31440 |
Fitment
| Year | Make | Model | Chassis | Submodel |
|---|---|---|---|---|
| 2005+ | Lexus | IS250 | DBA-GSE20 | 4GR-FSE 2.5L |
| 2005+ | Lexus | IS350 | DBA-GSE21 | 2GR-FSE 3.5L |
| 2005+ | Lexus | IS250 | DBA-GSE25 | 4GR-FSE 2.5L |
Sold individually. Lead times may apply — contact us at iilumolab for availability and shipping estimates.
iilumolab is an Authorised Australian Distributor of Koyorad Performance Radiators.
Shop with confidence — all Koyorad products sold through iilumolab are genuine, backed by manufacturer support, and shipped from Australia.
If you're unsure whether this will fit your vehicle, contact our team of experts via email at hello@iilumolab.com and send through a few photos of the car for us to verify fitment.
Installation
We always recommend professional fitment for guaranteed satisfaction. If you're wanting a hassle-free installation, feel free to contact our friendly team as we offer installation services in-store at our Melbourne workshop. For more details, contact us here.
Note
Upon receiving the item, please ensure that the part is indeed the correct item you have ordered. This can be achieved by checking labels on the packaging. Please also ensure a proper test fit of the item is conducted prior to paint and/or installation. Returns/Warranty claims will be voided if the item has been tampered with, or is no longer in resalable/new condition.