One of the quieter upgrades in any serious RB26 build is the thermostat. It doesn't make a sound, it doesn't show up in dyno graphs, and nobody photographs it at car shows. But a lower-temperature thermostat in a modified GT-R is one of the more impactful reliability upgrades available, especially for cars running elevated boost or doing track work where sustained high-performance driving generates heat the factory cooling system wasn't fully designed for.

The factory thermostat on a Skyline GT-R opens at around 76-82°C. This is appropriate for a standard engine because modern combustion efficiency improves as coolant temperature rises — you don't want a cold engine running rich on choke indefinitely. But for a modified GT-R where thermal management is a concern and the cooling system is being pushed harder than factory spec, having the coolant circulate at lower temperatures gives you more headroom before heat becomes a problem.

What the NISMO Thermostat Does

The NISMO Racing Low Temperature Thermostat (21200-RS580) opens at 62°C — significantly earlier than the standard unit. This means the cooling circuit opens to the radiator sooner, keeping coolant temperatures lower during normal driving and significantly lower during hard use. In a turbocharged engine where intake charge temperature is directly affected by coolant temperature (through heat soak in the intake manifold area), cooler running also translates to denser charge air and more consistent power output.

Fits RB and VG engine applications including the Skyline GT-R R32, R33, R34, and the Fairlady Z Z32. Direct replacement, no modifications required.

Important note: on a standard street car, a 62°C thermostat will cause the engine to run cooler than the factory heater system was calibrated for — you'll notice reduced cabin heating in cold weather. This is a known trade-off and the reason the NISMO thermostat is positioned as a racing/performance product rather than a general upgrade. If your GT-R sees track days or sustained performance driving in warm climates, the NISMO Racing Thermostat is a sensible addition to your cooling system overhaul.