IAG 156 Degree Low Temperature "EJ" Thermostat For 2002-2014 WRX, 2004-2021 STI

For Subaru owners pushing their 2002-2014 WRX or 2004-2021 STI EJ series engine to the limit, the IAG 156 Degree Low Temperature EJ Thermostat is a smart upgrade. Unlike the factory thermostat, which doesn’t open until 172.4°F (78°C), this unit starts opening at 156°F (69°C), improving cooling efficiency by allowing coolant to circulate sooner.

By allowing coolant to circulate earlier, a low-temperature thermostat helps to keep the engine from heating up too quickly. This is a big advantage for engines that see heavy loads, preventing sudden spikes in heat. A cooler engine can also mean better efficiency and less risk of detonation, allowing for stronger, more reliable performance.

The IAG 156° Thermostat is best suited for:

• Modified EJ engines making more power than stock
• Vehicles with upgraded cooling systems (radiators, fans)
• Track day or autocross cars
• Street cars in hot climates with ECU tuning to match

It's not recommended for:

• Daily drivers in colder climates
• Stock or lightly-modified Subarus
• Builds without supporting cooling upgrades

The IAG 156 Degree Low Temperature EJ Thermostat is engineered for durability, featuring a 304 stainless steel body to resist corrosion. This direct-fit replacement stands up to demanding conditions and includes the necessary gasket for a secure, leak-free seal to the thermostat housing. Every detail, from the laser-etched finish to the IAG corporate logo is a reflection of the high quality engineering and construction behind this component.