Type ‘C’ oil seal has an additional cup inserted into the outer cup of ‘B’ type. The supplementary metal inner ring provides a superior stiffness. This type is recommended for use in heavy polluted environments. As the static sealing between housing and metallic shell is limited, low viscosity media can “creep”.
They are best known for their bright light emission that is far reaching. Their tungsten is encased in a quartz tube filled with xenon gas. They may require more power when turned on but use much less of it to maintain brightness. Moreover, they have a longer lifespan compared to the halogens. They may seem better but they also present some limitations such as being more expensive as far as manufacturing and replacement is concerned. They are not easy to manufacture from their complex design. Their bright light cause a blinding effect to oncoming traffic which is undesirable and can cause dangers on roads.


Like any element of the engine, oil seals are subject to wear. Over time they can lead to possible leaks of lubricating liquid.