Click to zoom in
SKU: 15999-AM001 | UPC: 4957266653388
HKS 03-06 EVO / 08 EVO GSR/MR 75 degree Low Temperature Oil Cooler Thermostat
The HKS 15999-AM001 oil cooler thermostat opens at a low 75°C (167°F) to direct engine oil through the cooler for rapid temperature reduction during demanding conditions. Engineered for 2003-2006 Mitsubishi Lancer Evolution VIII/IX and 2008+ Evolution X GSR/MR models it maintains stable oil temperatures above freezing levels to avoid viscosity loss and ensure consistent lubrication. This direct-fit unit installs between the engine block and oil cooler line for immediate response and reliable cooling control.
Key Features
- 75°C Opening Point: Activates at lower temperature than stock for faster oil cooling without excessive drop in cold weather preserving oil film strength.
- Precision Valve Design: Smooth wax pellet mechanism responds quickly to temperature changes directing flow only when oil exceeds set point for balanced thermal management.
- Compact Aluminum Housing: Lightweight durable construction resists corrosion and withstands high-pressure oil flow in performance engines.
- Direct OEM Replacement: Matches factory mounting points on Evo 4G63 and 4B11 engines for bolt-on fit without modifications.
- Motorsport Tested: Proven in rally and circuit applications to hold oil temps steady under sustained high loads extending engine life.
Product Notes
- Pair with HKS oil cooler kit for full system efficiency.
- Inspect O-rings during install and replace if worn.
- Ships in protective packaging to prevent damage.
Installation Notes
- Professional installation recommended.
- Drain engine oil before removing stock sandwich plate.
- Uses existing M14x1.5 ports no additional hardware needed.
This Part Fits
| Year | Make | Model | Submodel |
|---|---|---|---|
| 2003-2005 | Mitsubishi | Lancer Evolution | VIII |
| 2005 | Mitsubishi | Lancer Evolution | VIII MR |
| 2005-2006 | Mitsubishi | Lancer Evolution | IX |
| 2006 | Mitsubishi | Lancer Evolution | IX MR |
| 2008-2015 | Mitsubishi | Lancer Evolution | X GSR |
| 2008-2015 | Mitsubishi | Lancer Evolution | X MR |
Why Choose HKS?
- Decades of JDM tuning leadership with Super Taikyu endurance wins.
- Components built to Formula drift and rally standards for real-world reliability.
- Exact engineering tolerances ensure leak-free operation under boost.
Frequently Asked Questions
-
Q: Does this fit all 2003-2006 Evo models?
A: Yes it bolts directly to Evolution VIII and IX including MR variants using standard oil sandwich plate location on 4G63 engine. -
Q: What material is the thermostat body?
A: CNC-machined aluminum with stainless steel internals for heat resistance and long-term durability in high-heat oil circuits. -
Q: Is warranty coverage included?
A: HKS offers manufacturer defect warranty contact seller for claims processing after verifying proper installation.
Shipping & Handling
- Method: UPS Ground or USPS Priority
- Availability: In stock - ships same or next business day
- Packaging: Secure box dimensions 4.72 x 3.94 x 2.36 inches
- Weight: 4.8 ounces
Cooling
Shop performance cooling parts at Black Ops Auto Works for premium radiators, thermostat housings, thermostats, coolant reservoirs, expansion tanks, radiator hoses, oil coolers, transmission coolers, fans and shrouds, water pumps, and thermal management upgrades for street, track, towing, diesel, and high-horsepower builds. Whether you are trying to control engine temps, improve reliability, or support demanding performance use, this collection is built around proven cooling-system upgrades for serious enthusiasts. Shop Cooling Parts by Category Browse automotive cooling system components across key product categories, including: Radiators Coolant reservoirs and expansion tanks Thermostat housings and thermostats Radiator hose kits and silicone coolant hoses Oil coolers and oil cooler accessories Transmission coolers Coolant bypass kits and coolant filters Fans and shrouds Radiator caps Water pumps Radiator shrouds, radiator stays, and cooling plates Thermal wrap, thermal tape, an...
View Cooling Products
Engine
Shop engine parts, oil catch cans, engine cooling upgrades, thermostats, thermostat housings, radiators, coolant accessories, supercharger pulleys, idler pulleys, tensioner pulleys, throttle bodies, engine covers, fuse box covers, cap covers, valve covers, oil system parts, ignition parts, sensors, gaskets, fuel delivery parts, and engine bay dress-up accessories at Black Ops Auto Works. This collection is built for performance vehicles, trucks, SUVs, muscle cars, boosted builds, HEMI platforms, Hellcat builds, Trackhawk SUVs, RAM TRX trucks, LS-powered builds, and high-horsepower street or track applications. Whether you are improving oil control, reducing heat soak, upgrading cooling, supporting higher boost, cleaning up the engine bay, replacing worn engine components, or preparing a street car for harder driving, this collection helps you shop engine parts by brand, category, vehicle platform, and performance goal. Shop Engine Parts by Category Browse engine upgrades and replace...
View Engine Products
HKS
HKS is a Japanese manufacturer of premium performance parts founded in 1973 that has been at the forefront of turbocharged engine development, producing turbochargers, exhaust systems, engine management, intercoolers, and supporting performance components for some of the most iconic Japanese sports cars ever built. The brand's GT and GTIII turbocharger series, Super Sequential Blow Off Valves, and Racing Suction intake kits are recognized globally as benchmark-quality products that combine Japanese manufacturing precision with decades of motorsport development experience. HKS products are particularly well-known in the Toyota Supra, Mitsubishi Evo, Subaru STI, Nissan GT-R, and Honda NSX communities, where the brand's heritage in building the world's fastest versions of these cars has created a loyal following among enthusiasts who want the best available components. From a simple racing suction kit to a complete GT turbo with intercooler and ECU tune, HKS provides an end-to-end perf...
View HKS Products
Oil Coolers
Welcome to our exclusive Oil Coolers collection, where performance meets efficiency! Our curated selection of oil coolers is designed to enhance the cooling capabilities of your engine, ensuring optimal performance and longevity. Why Choose Our Oil Coolers? High-Quality Materials: Each oil cooler is crafted from durable materials to withstand extreme conditions. Enhanced Performance: Our products are engineered to reduce oil temperatures, improving engine efficiency. Easy Installation: Designed for straightforward installation, our oil coolers are user-friendly for both professionals and DIY enthusiasts. Compatibility: We offer a variety of models that fit a wide range of vehicles and machinery. Featured Products Explore our top-rated oil coolers: Universal Oil Cooler: A versatile choice suitable for various applications. High-Performance Racing Oil Cooler: Perfect for racing enthusiasts looking for peak performance. Compact Oil Cooler: Ideal for smaller vehicles with li...
View Oil Coolers Products