Performance Thermostats

The best performance thermostats in this collection are the Mishimoto racing thermostats for Subaru, Mitsubishi, and Nissan cars, including the 68-degree Celsius unit for the 2015-2025 WRX and 2014-2018 Forester XT, the long-running WRX and STI fitment for 2002-2014 cars, and versions for the BRZ, EVO 8 and 9, EVO X, 350Z, 370Z, and GT-R, plus a Gates 170-degree thermostat for the 2002-2014 WRX and 2004-2019 STI. Each one opens earlier than a typical factory thermostat, so coolant starts circulating sooner.

A thermostat is a temperature-controlled valve between the engine and the radiator. It stays closed while the engine warms up, then opens at its rated temperature to let coolant flow. A lower-rated performance thermostat opens sooner, which can help a hard-driven or track-used engine shed heat earlier, but it also changes how quickly the engine reaches operating temperature on a cold morning. That trade-off is why fitment and rating both matter: match the part to your exact engine, and think about whether the car is a daily driver, a track car, or both before choosing the coolest rating on the shelf.

Mishimoto supplies most of this collection, and its racing thermostat line is built around model-specific fitments rather than one universal part, covering Subaru, Mitsubishi, Nissan, Honda, and Scion applications in these listings, plus a thermostat and housing assembly for the 370Z and G37 and an in-line oil thermostat for universal oil-cooler plumbing. Gates is the other name here, a long-established maker of belts, hoses, and cooling-system service parts, represented by its 170-degree thermostat for the WRX and STI. Together they cover the two ways most owners shop this job: a performance-rated unit for a modified car, or a service-grade replacement from a cooling-system specialist.

Start with the Mishimoto racing thermostat for the 2015 and newer WRX, the earlier WRX and STI racing thermostat, or the Gates 170-degree thermostat. A thermostat works as part of a system, so also browse the wider cooling range and performance radiators if you are refreshing the whole setup, and read our guide on why you should install an intercooler kit for the charge-air side of temperature control.

Why fit a lower-temperature thermostat?

It opens earlier, so coolant reaches the radiator sooner under load. That can help modified and track-driven engines manage heat, but street cars should weigh it against slower warm-up in cold weather.

Does a racing thermostat add horsepower?

Not by itself. It is a supporting part that helps the cooling system keep temperatures consistent, which protects the power the engine already makes during hard use.

Is a thermostat hard to install?

It is a moderate job on most of these cars: drain some coolant, swap the unit and gasket at the thermostat housing, refill, and bleed air from the system. Check your year and model for housing location, and never open a hot cooling system.

Can a cooler thermostat cause problems on a daily driver?

It can make warm-up take longer and may keep coolant temperatures lower than the engine management expects in very cold weather. If the car is a year-round daily, choose the rating with that in mind rather than defaulting to the lowest.