The stock oil cooler thermostats don’t fully open until an absurd 230F! This combined with Mazda’s recommendation to run 5w20 oil is a big reason why these motors exhibit significantly more internal wear than previous rotaries, particularly to the side irons and bearings. Mazda made major compromises to get these cars to pass regulation, and longevity suffered as a result. These direct replacement oil cooler thermostats open at a much more reasonable 180F. This combined with a proper weight oil such as 15w40 and running premix can double the life of the motor. Depending on what model rx8 you have, you may need 1 or 2 of these.
-180F opening temperature.
-Direct replacement for the factory oil cooler thermostat.