Car valve stem seals

How to detect the valve stem seals failure

To check the valve stem seals serviceability, start the vehicle engine, warm it up and gradually increase the revs to 4,000 per minute. Ask an assistant to watch the exhaust pipe. If blue-gray smoke starts coming out of the tailpipe after you have sharply released the accelerator pedal, this means that the valve stem seals are worn out. At a service station you can check the CH2 level in the exhaust gas with the help of special equipment: if its content exceeds the norm, it means that oil gets into the exhaust system, which may also show that the components have to be replaced.

You may identify that the valve stem seals need diagnosis, by the following signs:

• increased oil consumption;
• grey-blue or blue smoke from the exhaust pipe;
• formation of carbon deposits on spark plugs;
• premature oil contamination;
• loss of engine power, its unstable operation.

Causes of the valve stem seals failure

The valve stem seals operate in severe conditions: at a crankshaft rotation speed of 500 to 4,500 revs per minute, every valve makes 150 to 1200 operating strokes. The higher the engine speed, the more stress the seals are exposed to. As a consequence, frequent driving at increased revs can considerably shorten their service life.

Aggressive chemical substances present in the composition of oil, gasoline and exhaust gas, have a disruptive impact on the components. Eventually the material from which they are produced, loses its elasticity, due to which the seal loses the tightness of its fit to the valve stem. Therefore, valve stem seals should be replaced every 80,000-100,000 km on the average. But low-quality components can fail much faster.

Use of poor-quality or unsuitable oil in the lubrication system, neglecting its replacement schedule, a clogged oil filter also promote accelerated wear of components.

Replacement of valve stem seals

Valve stem seals are consumables, so they are not repairable. Worn out components are replaced with new ones. Installing new parts by yourself, if you have no relevant experience, is not only difficult, but also hazardous: in most cases, this procedure involves dismantling the cylinder head and numerous accessory equipment. For the valves removal you will need a special valve spring compressor tool. To avoid damaging the guide sleeves, old seals must also be removed with the help of an appropriate tool - a collet remover. For pressing in new parts you will need a mandrel of a certain diameter. To prevent installation errors that considerably increase the risk of engine failure, contact a service station to replace the valve stem seals.