- Remember, while you can save money by doing this task yourself, if you're unsure or uncomfortable, it's best to seek professional assistance. Regular spark plug replacement, as recommended by the manufacturer (usually every 30,000 to 100,000 miles), can help prolong your engine's life, maintain optimal performance, and potentially avoid more costly repairs down the road.
By first finding out the dimensions of the inner and outer diameters and the height of the bore, you have all the data for the correct size of the oil seal. Of course, the oil seal must also be able to withstand the pressure, temperature and medium it is exposed to within the seal during the manufacturing process. You can read more about this in our oil seal selection guide.
The lip is specially designed to ensure the oil seal works effectively with the different forces that arise during rotation. Many different designs and materials are used, so countless types of oil seals are available. These are chosen according to the application; pumps, gearboxes, wheels, and many other rotating applications where fluids need to be sealed. They are used in a variety of sectors, such as the chemical industry, manufacturing, wind turbines, automotive sector, food industry, and more. Oil seals are used in nearly all sectors.
Figure 9: Items relating to oil seal characteristics
The cover is fixed by nuts or bolts on top, or by screws round the edge. Loosen them all and remove them with their washers. If there are several oil-sealing washers under each fixing, note their order.
Its sealing edge comes in full contact with the shaft surface in order to provide excellent sealing performance.
(See Figure 3.)

Oil seals are available in an immense range of sizes, for shafts from a few millimetres to several metres. Once the shaft diameter, groove diameter (housing diameter) and groove width are known, selecting an appropriate oil seal is a simple task. An oil seal or its product description is usually associated with three dimensions, for example 6x15x4. These refer to the sizes of the hardware for which the oil seal is designed. In this example, this oil seal is suitable for: 6-mm shaft diameter x 15-mm groove diameter x 4-mm minimum groove width.
The lip is specially designed to ensure the oil seal works effectively with the different forces that arise during rotation. Many different designs and materials are used, so countless types of oil seals are available. These are chosen according to the application; pumps, gearboxes, wheels, and many other rotating applications where fluids need to be sealed. They are used in a variety of sectors, such as the chemical industry, manufacturing, wind turbines, automotive sector, food industry, and more. Oil seals are used in nearly all sectors.


Regular inspection and maintenance of oil seals are essential to identify signs of wear, damage, or leakage. Proper lubrication and adherence to recommended service intervals can help extend the lifespan of oil seals. When replacement is necessary, selecting the correct seal type and ensuring proper installation are critical to maintaining the integrity and performance of the equipment.
Once you have selected the most suitable seal available, considering the environment, temperature, shaft speed, pressure, lubrication availability, as well as the size, of course, the seal should be stored adequately and then fitted properly. Here are a few suggestions that could help:-

318 valve cover gasket. The old gasket must be carefully removed, and the surface of the valve cover and cylinder head cleaned before installing the new gasket. It is important to torque the bolts to the specified requirements to ensure a proper seal and prevent any leaks.