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
Cooling system parts and accessories for HEMI, Hellcat, Trackhawk, Duramax, Cummins, and import performance builds are stocked at Black Ops Auto Works. Shop radiators, thermostats, thermostat housings, water pumps, coolant reservoirs, expansion tanks, radiator hoses, oil coolers, transmission coolers, fans and shrouds, and thermal wrap for street, track, towing, and diesel platforms. Every product is filterable by year, make, model, trim, engine, and drivetrain so the correct part ships the first time. Black Ops Auto Works carries 2116 Cooling SKUs across radiator, thermostat, water pump, hose, and heat management categories. What This Category Covers The Cooling category groups together every part that keeps engine, transmission, and charge air temperatures in check under real driving load. Coverage spans aluminum performance radiators, billet thermostat housings, high flow water pumps, silicone radiator hose kits, coolant reservoirs and expansion tanks, oil and transmission co...
View Cooling Products
Engine
Engine parts and engine bay upgrades for Dodge, Jeep, RAM, Chrysler, Chevrolet, Ford, Toyota, Nissan, Subaru, and Honda vehicles are stocked at Black Ops Auto Works. Shop oil catch cans, supercharger pulleys, thermostats, radiators, cooling parts, throttle bodies, intake manifolds, headers, ignition coils, spark plugs, sensors, gaskets, fuel pumps, valve covers, engine covers, billet cap covers, and full engine bay dress-up parts for HEMI, Hellcat, Trackhawk, Redeye, Demon, Scat Pack, RAM TRX, LS, LT, Coyote, EcoBoost, K-Series, and 2JZ builds. Every product is filterable by year, make, model, trim, engine, and drivetrain so the correct part ships the first time. Black Ops Auto Works carries 14,298 engine SKUs across performance, cooling, oil control, ignition, and appearance categories. What This Category Covers The Engine collection combines OEM-replacement engine service parts with performance aftermarket upgrades for supercharged, turbocharged, and naturally aspirated builds...
View Engine Products
HKS
HKS Japanese performance parts for Toyota Supra, Nissan Skyline GT-R, Nissan Silvia and 240SX, Subaru WRX and STI, and other JDM platforms are stocked at Black Ops Auto Works. Shop turbo kits, cat back exhaust systems, coilovers, blow off valves, and engine management upgrades for RB26DETT, SR20DET, 2JZ-GTE, and EJ series turbocharged engines. Every product is filterable by year, make, model, trim, engine, and drivetrain so the correct part ships the first time. Black Ops Auto Works carries 607 HKS SKUs across forced induction, exhaust, suspension, and engine management categories. What This Collection Covers HKS has built its reputation on Japanese sport compact and sports car performance since the late 1970s, developing turbo kits, exhaust systems, and suspension for platforms including the Toyota Supra 2JZ-GTE, Nissan Skyline GT-R RB26DETT, Nissan Silvia and 240SX SR20DET, and Subaru WRX and STI EJ and FA series engines. This collection brings together fitment verified HKS pa...
View HKS Products
Oil Coolers
Oil Coolers parts and accessories Performance oil coolers and oil cooling kits for cars, trucks, SUVs, track cars, towing rigs, diesel builds, and forced induction projects are stocked at Black Ops Auto Works. Shop direct fit oil cooler kits, universal plate coolers, thermostatic sandwich plates, oil cooler fans, service packs, fittings, and mounting hardware for better temperature control under load. Every product is filterable by the relevant shopping criteria so the correct item ships the first time. Black Ops Auto Works carries 225 Oil Coolers SKUs across direct fit kit, universal cooler, thermostat, fan, fitting, and service component categories. What This Category Covers An oil cooler adds heat rejection capacity when engine oil works harder during towing, track use, extended boost, high ambient temperatures, or repeated acceleration. This collection covers complete vehicle specific systems and universal components that require a planned installation. Direct Fit and Univer...
View Oil Coolers Products