To replace the car's timing belt, degrease the engine, drain the coolant, remove the old belt, insert a new belt in the place of the old one, replace the crankshaft seal with a new one and refill the coolant. For proper replacement instructions, refer to the owner's manual.
First, cushion the engine from contamination by cleaning it with degreaser. Once the engine is clean, check the owner's manual or mechanic's book for the car's firing order.
Position up the first cylinder by detaching the spark plug, inserting a screwdriver in the hole of the spark plug, disconnecting the battery cables and detaching the radiator cap. Drain the coolant into a suitable collecting jar, and detach the drive belts, radiator hoses, fan, water pump and crankshaft pulley. Uncover the timing belt, mark its reference point, loosen the tension gear and pull the belt from the engine.
Lubricate the tension gear, fit the new belt over the gear, align the belt with the reference mark, replace the camshaft bolts and fasten the gear. Remove the crankshaft seal, and insert a new one into the timing cover. Apply oil to the seal, and replace the timing belt cover. Replace the fuel and water pumps, clutch, and fan. Refill the engine coolant according to the manual, replace the belts and hoses, and then rewire the battery. Finally, test the new belt.