Aero Shutter (active grille) Modification

thingiverse

**Overview-** These parts apply to the “aero grille shutter” function that may be fitted to GM 1.4 (LUJ) engine “ECO” vehicles including gen1 Cruze and perhaps others. No diagnostic trouble codes (DTCs) should be set during operation because the motor will continue to operate within its normal rotation range but will not drive the shutters closed. The installation of these parts is described in great detail on the CruzeTalk forum at- https://www.cruzetalk.com/threads/how-to-electrical-control-of-the-1-4t-luj-thermostat-and-defeating-aero-grille-shutters.255195/ **Background-** If you feel that your vehicle runs too hot and you have either changed the thermostat’s wax motor to a lower temperature type (such as 180F/82C) or you have driven the internal thermostat heater electrically to lower its temperature, the engine may still run hot under certain circumstances. The problem is that the engine controls on vehicles equipped with grille shutters will close them at sustained highway speeds (such as 45+mph/72+kmh for more than 15 minutes). When this happens, as much as **70%** of the air inlet area will be blocked. The radiator will then have insufficient airflow under some operating conditions and so the engine temperature can still rise up close to the original setpoint. The engine controls will then open and close the shutters to keep it there, so it defeats the modifications that were made to the thermostat. Restricting airflow in this manner also chokes off airflow to the engine’s turbo intercooler and transmission cooler (if fitted). So overall it is a questionable thing to do despite any marginal gains in fuel economy that may be gained by doing it. Only by allowing adequate airflow during all modes of operation can the thermostat be allowed do its job properly, even in its original unmodified state. The parts for this modification consist of a rotor and a cage. The rotor fits into the grille motor housing and the cage restrains its range of motion to approximately 90 degrees (right angle) of motion. The motor will then "think" it is connected to the shutters but they will actually be propped open, or can be removed entirely. The mounting holes in the cage are designed so that #6 or M4 screws will thread into them while making their own threads in the plastic.