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Valve stem seals: replacement and selection

When and why it is necessary to replace valve stem seals

Lifetime limit of the valve stem seals is 150,000 – 200,000 kilometers of mileage. The components are to be replaced in case of rubber elasticity loss, its delamination from the base. Accelerated wear-out of the parts occurs due to usage of poor-quality motor oil, oil starvation or overheating of the engine.

You can detect that the valve stem seals are worn out by a few signs: excessive oil consumption is noticeable, bluish smoke comes from the exhaust pipe at accelerator pedal pressing, oil appears on the spark plugs thread.

The valve stem seals are replaced by a kit. The procedure is performed at a service station, as engine servicing works require high qualification. Moreover, a special tool for demounting of the valves and stem seals is used during components replacement. While performing this, it is necessary to install a new camshaft oil seal, a valve cover gasket and ignition distributor o-ring.

How to select valve stem seals

By production material there are valve stem seals made of fluororubber and acrylate rubber. These materials provide high degree of sealing, and do not lose their operational characteristics at regular contact with lubricants.

Efficient removing of oil excesses during valve operation, and prevention of its ingress into a combustion chamber can be performed by high-quality valve stem seals from well-known manufacturers only. They are such firms as Ajusa, JP Group, Goetze, Febi Bilstein, Topran and others.

During components selection give preference to those recommended by the manufacturer for cars of the certain model, configuration and production year. In this case, the valve stem seals will fit by inner and outer diameters and the inner surface shape. Also thickness of walls, which is defined by construction of the valve guide sleeves, is no less important.