The thermostat on the 1992 Subaru Legacy Turbo mounts to the lower half of the water pump. This is the standard location for most import vehicles. This allows the thermostat to regulate the temperature by monitoring the fluid before it enters the engine. This differs from a thermostat mounting on the top of the engine that monitors fluid temperatures as the fluid exits the engine.
Tools Used: Tools, Drain pan, Pliers, Socket set
Open the drain valve located on the bottom of the radiator with a pair of pliers and drain the contents of the radiator into a clean drain pan. Close the drain valve once finished. Locate the water inlet housing bolted onto the water pump by following the lower hose from the radiator to the location where the hose mounts to the water pump. Loosen the band clamp on the radiator hose and then pull the hose off the water inlet. Remove the two nuts that hold the water inlet onto the studs located on the water pump. Pull the water inlet off the water pump.
Take note of the thermostat’s orientation inside the water pump. There is an arrow on the thermostat that rests between the two studs on the water pump. Mark the location and pull the thermostat out of the water pump. Place the rubber O-ring gasket on the thermostat. Use the old thermostat for a visual aid on how this looks. Place the thermostat back into the water pump and orient it correctly. Place the water inlet cover back onto the water pump and secure it with the two nuts. Place the hose back onto the water inlet, and secure the hose with the band clamp. Drain the fluid back into the radiator.