Lesson 3/Learning Event 1
If the smoke has a blue color, oil is reaching the combustion chamber. This could be caused by bad rings,
worn intake valve guides, or oil leaking through the head gasket. In any case, the vehicle should go to your
support maintenance for more checks.
If the engine is warmed up and the exhaust smoke is white, water is getting into the combustion chamber.
This could be caused by a leading head gasket or a cracked head or engine block. This is also a job for your
The exhaust can also provide a clue if one or more cylinders are not firing. Place you hand about 3 inches
from the end of the tail pipe and in line with the exhaust gases as they leave the pipe. The pressure of the
gases against you hand should be almost steady, with a slight increase every time a cylinder fires. If a cylinder
fails to fire, you can notice it by a drop in the pressure against your hand.