The Ford Focus is a small front-wheel drive car introduced in North America in 1999 as a 2000 model. Ford made very few changes to the Focus in subsequent years. Like the original, the 2002 Focus was available in hatchback, sedan and wagon models. The Focus uses a liquid-cooled four-cylinder engine. A thermostat regulates the cooling system temperature. A faulty thermostat can cause your Focus to overheat, making thermostat replacement necessary.
Open the bonnet and allow the engine to cool off before beginning this procedure.
Remove the filler cap from the radiator expansion tank at the front of the engine bay. Place a drain pan under the front of the car under the radiator. Loosen the radiator drain plug with a pair of pliers and allow the coolant to fully drain into the pan. Tighten the drain plug and remove the drain pan from under the car.
Locate the coil pack which is to the right of the engine block. Push in on the release tab on the underside of the wiring connector on the coil pack, then pull the connector straight out of the coil pack.
Remove the bolts from the exhaust gas recirculation tube brackets to the right of the engine block with a socket and ratchet. Push the tube downwards to gain access to the thermostat housing.
Remove the hose clamps from both ends of the thermostat housing by squeezing the tabs together with a pair of pliers, then sliding the clamps from the housing. Pull the hoses straight off of the housing. Remove the retaining bolts from the housing with a socket and ratchet.
Pull the thermostat housing from the engine block. Remove the two remaining hoses from the housing by removing the clamps with a pair of pliers, then pulling the hoses from the housing. Remove the housing from the engine bay.
Remove the screws from the thermostat housing retaining ring with a Torx screwdriver. Remove the retaining ring and place it aside. Pull the thermostat out of the housing and discard it.
Insert a new thermostat into the housing and replace the retaining ring. Install the housing back into the engine bay by reversing the removal procedure.
Place a funnel into the opening of the radiator expansion tank. Pour the coolant from the drain pan into the tank. Remove the funnel and replace the cap. Close the bonnet.
Always replace a thermostat with one of equal temperature rating as the original. The temperature rating should be stamped on the thermostat. Use of a thermostat with a different temperature rating may cause your engine to run too cool or too hot, possibly causing engine damage.