The cooler ISR PERFORMANCE thermostat for VQ35HR and VQ37VHR engines. A great upgrade for high performance engines, ISR units open at 68 degrees Celsius compared to the factory 78 degrees Celsius. Cool your engine before heat builds up!

Once the engine is fully warmed up, the ISR thermostat opens at a lower temperature than standard thermostats, allowing coolant to circulate through the engine more quickly, reducing and maintaining engine temperature.