The replacement of broken valve springs and defective valve stem seals may be performed without the removal of the cylinder heads, and is commonly done with two special tools and a source of compressed air. Start with the valve cover, camshaft, the lifters and observe that in the 2.0L four-cylinder there is a requirement to have the cylinder head removed to get to the camshafts. Take off the spark plug of the cylinder which contains the defective part and in case you take off all the seals of the valve stems, take off all the spark plugs. Rotate the crankshaft until the piston in the given cylinder reaches Top Dead Center on the compression stroke one cylinder at a time in the firing order. Insert an air hose connector into the spark plug hole and hook it up to a pressurized air source forcing air into the valves to keep them in place. Insert stuff shop rags into the holes in the cylinder head to ensure that parts will not collect in the engine. Tap the top of each valve spring retainer to loosen the connection between the valve keeper and the spring retainer and carefully trim the spring to take the keepers out with the help of a valve spring compressor. Take away the valve spring and retainer, remembering that in case air pressure does not hold the valve down, the cylinder head might have to be taken off to fix it. Take off the old valve stem seals, taking note to differentiate between intake and exhaust seals. Tape or wrap a rubber band around the top of the valve stem to ensure that it does not fall into the combustion chamber and then release the air pressure. Check the valve stem damage and look at the eccentricity of the movement of the valve and binding in the guide, that can be the sign of bent valve or broken guide, in this case, the head of the valve has to be removed and then repaired. Use air pressure again to hold the valve in the closed position, and remove the tape or the rubber band. Coat the valve stem with engine oil and replace the valve guide seal using a new one and beating it in the slot. Fit the valve spring and retainer, squeeze the spring, and place the keepers on carefully and place a small dab of grease to hold them in. Lift the pressure of the spring tool and make sure that the keepers are in place. Turn off the air hose and take out the adapter of the spark plug hole and fit in the camshaft, lifters, timing belt, and valve cover. Lastly, screw the spark plug(s) into place and the ignition coil(s), change the engine on and listen to it, looking out of the valve cover region.