Nissan 13207-D4201 Seal-Oil,Valve

Broken valve springs and defective valve stem seals can be replaced without removing the cylinder heads, typically requiring two special tools and a compressed air source. Begin by removing the intake plenum and valve covers, followed by the timing chain, camshafts, and lifters from both cylinder heads. Remove the spark plugs and turn the crankshaft until the piston in the affected cylinder is at Top Dead Center on the compression stroke. If replacing all valve stem seals, start with cylinder number one and work through the firing order. Thread a long adapter into the spark plug hole and connect an air hose from a compressed air source. Due to the length of the spark plug tubes, a long spark plug adapter with a hose attached is necessary. Apply compressed air to the cylinder and stuff shop rags into the cylinder head holes around the valves to prevent parts and tools from falling into the engine. Use a valve spring compressor to compress the spring, releasing the valve stem keepers, which can be lifted out with a magnet or needle-nose pliers. The valves should be held in place by air pressure; if they cannot hold air, the cylinder head should be removed for a valve job. Remove the spring retainer, valve spring, and valve stem seal, then wrap a rubber band or tape around the top of the valve stem to prevent it from falling into the combustion chamber before releasing the air pressure. Inspect the valve stem for damage, ensuring it does not bind in the guide; if it does, the cylinder head will need to be removed for repair. Reapply air pressure to retain the valve in the closed position, lubricate the valve stems with engine oil, and install new valve stem seals using a special tool or a deep socket and hammer. Install the valve spring with the more closely-wound coils and paint mark toward the cylinder head, followed by the valve spring retainer. Compress the valve springs and position the keepers in the groove, applying a small dab of grease to hold them in place. Remove the pressure from the spring tool and ensure the keepers are seated, then disconnect the air hose and remove the adapter from the spark plug hole. Reinstall the camshafts and lifters, then the timing chain, valve covers, and spark plugs, along with ignition coils and the upper and lower intake plenum. Finally, start the engine and check for oil leaks and unusual sounds from the valve cover area.

Broken valve springs and defective valve stem seals can be replaced without removing the cylinder heads, typically requiring two special tools and a compressed air source. If the head remains on, a special on-vehicle valve spring compressor should be obtained, ensuring the correct spring compressor is available before starting. If special tools are unavailable, the heads must be removed to use a clamp-type valve spring compressor. Begin by removing the upper intake manifold and valve cover(s), followed by the timing chain, camshafts, and lifters from both cylinder heads. Remove the spark plugs and turn the crankshaft until the piston in the affected cylinder is at Top Dead Center. For replacing all valve stem seals, start with cylinder number one and work through the firing order, turning the crankshaft 120 degrees to bring the next cylinder to TDC. Thread a long adapter into the spark plug hole and connect an air hose from a compressed air source, using a long spark plug adapter with a hose attached. Apply compressed air to the cylinder and stuff shop rags into the cylinder head holes around the valves to prevent parts and tools from falling into the engine. Use a valve spring compressor to compress the spring, releasing the valve stem locks with small needle-nose pliers or a magnet. The valves should be held in place by air pressure; if they cannot hold air, the cylinder head should be removed for a valve job. Remove the spring retainer and valve spring, then the valve stem seal. Wrap a rubber band or tape around the top of the valve stem to prevent it from falling into the combustion chamber, then release the air pressure. Inspect the valve stem for damage, ensuring it doesn't bind in the guide; if it does, the cylinder head will need to be removed for repair. Reapply air pressure to retain the valve in the closed position, then remove the tape or rubber band. Lubricate the valve stems with engine oil and install the new valve stem seals, using a special tool or a deep socket and hammer to tap the seal until seated. Install the valve spring over the valve with the more closely-wound coils and paint mark toward the cylinder head, then install the valve spring retainer. Compress the valve springs and carefully position the valve stem locks in the groove, applying a small dab of grease to hold them in place. Remove the force from the spring tool and ensure the valve stem locks are seated, then disconnect the air hose and remove the adapter from the spark plug hole. After replacing all seals, position the crankshaft at TDC, install the camshafts and lifters, then the timing chain. Finally, install the valve covers, spark plugs, ignition coils, and the upper intake manifold, and start the engine, checking for oil leaks and unusual sounds from the valve cover area.

Loosen the cylinder head and put it on a hard surface or better still a working table. Apply a large clamp type of valve spring compressor that has an adapter where by when compressing each valve spring, the bottom section of the tool should be placed under the valve being compressed. Wind the spring just to the extent that you will be able to remove the keepers with a magnet or small pliers. Withdraw the valve spring together with the retainer and then carefully take out the rusted valve stem oil seal with the help of the pliers. Examine the exterior and the stem of the valve for excessive wear, and turn the valve relative to its guide to determine if it moves off center, if so then the valve is bent. Wipe the valve up and down in the guide and if it sticks the groove must have become rotated or the guide worn and the cylinder head will have to be machined. Apply a drop of oil on the valve stem before positioning the valve in the cylinder head; you need to place a plastic protector around the new rubber seal as it is fitted to avoid damaging it. If a seal protector is not available, crowd cellulose tape around the valve stem. Apply multi- purpose grease on the new seal and fit it over the valve stem and remove the protector or tape on it. Lightly engaging a deep socket of the right size, give the new seal a tap and place it down on the top of the valve guide. Align the spring over the valve along with the retainer engaged, then using the fingers and a small hammer, squeeze the valve spring and retainer and then engage the keepers on the groove with a small amount of grease if needed. Remove the pressure in the spring tool and make sure that the keepers are properly locked in place. After that, re-attach the lifters and camshafts back then finish the process by following the removal process in the opposite manner. Ignition of the engine and ensure that there is no signs of oil stains and strange noises coming from the valve cover.

Broken valve springs and defective valve stem seals can be replaced without removing the cylinder heads.

If replacing all valve stem seals, start with cylinder number one and work on one cylinder at a time, following the firing order sequence.

Remove the compressed air and reinstall the camshaft, lifters, timing chain, valve covers, spark plugs, and spark plug wires. Finally, start and run the engine, checking for oil leaks and unusual sounds in the valve cover area.