A valve plays a key role in regulating the air-fuel mixture in the combustion chamber. And it is the seal that keeps the oil from getting sucked down. When it starts to wear out, it beings to show certain distinct symptoms including- blue exhaust smoke, high oil consumption, loss of acceleration, reduced output power, etc. It is recommended to learn to recognize the symptoms of valve seals failure so that you will be able to replace the seal before any kind of serious damage done to your vehicle’s engine.