Q: How do you replace a thermostat on a 2006 mercury mariner

Hello. Thank you for writing in. The basic procedure for replacing the thermostat is pretty simple. You start by accessing the thermostat. Remove the hoses and retaining screws, and then removing the housing. Replace the thermostat outside and inspect the housing for any damages. Make sure the housing and the hoses are clean and in good condition. Remove and clean off any old gaskets. Reconnect the hosing and the housing. Refill the coolant to proper level, and test the repair. Make sure the thermostat is installing correctly, as it is not impossible to install them upside down. The unit is located at the top of the engine and is relatively easy to locate and manipulate. For assistance replacing the thermostat, contact our service department to schedule an appointment.