Changing the thermostat on the 2.5 engine is not the easiest of jobs. It is difficult to access. You need just about every extension length made. The job is much easier if you first remove the EGR pipe. Get the EGR pipe gaskets before you start. The original thermostat is vented. It is also expensive. Aftermarket thermostats are not vented. You must also purchase the grooved "O" thermostat seal if you go aftermarket. The vent should be facing the top when installed properly.