First of all, remove the engine cover, drain the coolant, disengage the ECT sensor, unscrew it, replace its O-ring, and finally reverse the process to install. Then do the same for 2003-2006 Acura and Honda Models from 2005. For 2007 Acura models with two ECT sensors, lift the vehicle, remove the splash shield, drain coolant, disconnect the sensor, replace the O-ring, and reverse that procedure for installation.