White smoke when startup - White smoke coming out of the
exhaust engine can signal a serious problem with the vehicle except the
2-stroke engine. This is because the two stroke engine have back up oil which
normally enters the fuel chamber to lubricate the piston.
While on the 4 stroke engine, this certainly should not
happen because the piston lubrication process is done from the bottom. Whether
on a motorcycle or a car, these white smoke symptoms are equally caused by the
presence of oil in the combustion chamber.
Supposedly, the engine combustion process on the 4-stroke engineconsists
only of fuel, air and fire. If there is an additional form of oil, then the
substance contained in the oil will caused white smoke when burned in the
combustion chamber. This symptoms can appear when startup or accelerating
So, what causes oil entering the combustion chamber?
There are several things that cause the oil entering
combustion chamber, and burn that produce white smoke. But this is not only due
to cylinder block wear, as there are many other components related to engine
oil like.
1. Valve stem oil damage
The main function of the valve on a 4 stroke engine is to
open the space between the intake / exhaust channels to the combustion chamber.
The opening of the valve will allow air to flow into the combustion chamber
during the intake process and discharge of residual burning during the exhaust
process.
But, the valve mechanism is driven by a series of camshafts
located inside the cylinder head. because the mechanism contains a lot of
friction then engine oil also lubricates this section. On the other hand, the
oil should not enter the intake of the manifold because it can make the oil entering
the combustion room. That's why there is a valve stem to avoid it.
But it's different when the seal is brittle or cracked. Oil
can enter easily when the valve moves up and down. Entrance of oil into the
intake channel will make the oil enter the fuel chamber during the suction
process, so it will burn.
2. The cylinder head gasket is broken
The main function of the cylinder head gasket is to close
the connections between the two components of the engine block and the cylinder
head which are both made of metal. This density is used to avoid leakage of
compression and mixing of oil and engine coolant.
This is because the waterjacket and oil feed extends from
the cylinder head to engine block. but if there is a crack path on the gasket, it
will cause oil out of oil feed follow the crack path. And if the crack is leads
in the combustion chamber, automaticly oil always drips the combustion room and
causes white smoke.
3. PCV System Damage
PCV (Positive crankcase ventilation) is a system used to
stabilize air pressure within the crank or crankcase chamber. The pressure
inside the crankcase may vary due to the effects of the downward piston
movement. Of course if the pressure inside the crankcase is , it will inhibit
the piston rate.
The PCV channel snaps from the crank chamber to the air
duct, but since the crank chamber is also filled with oil then it is inserted a
separator which prevents liquid oil from entering PCV so that only oil vapor enters
PCV. But many cases where this separator is damaged.
Of course if this channel breaks down it will make the oil
potentially rise to the PCV channel and out into the air ducts connected into
the intake manifold.
4. Oil leak from Turbocharger
img by pelicanparts.com
Originally turbo component is only placed on diesel engines,
because according to the character that has a high compression then the turbobecoming
very useful engine compartment. But for now, there are many turbo gasoline
engines. That's because the compression ratio of the latest gasoline engine is
also high, so the air supply must be maximized.
Turbo works like an air compressor, which pumps air from the
outside into the intake manifold. The turbo power source comes from the engine
exhaust thrust, this will drive the turbine to spin. Because it deals with heat
and friction, the turbo also has a cooling and lubrication circuit.
Engine oil is used to lubricate the turbo components
supplied through the oil line of the cylinder block. With its extreme enough
working conditions to make the turbo components become quite sensitive, so
engine oil is also potentially leaking. This oil leak can enter the exhaust or
into the intake.
If the oil exits to the exhaust, the oil will be burned by
the heat of the engine exhaust gas in the catalytic converter. So the smoke
produced is white, if the oil is out to the intake then the oil will enter the combustion
room and come burned during the power stroke that produces white smoke.
5. Wear of piston rings and cylinders block
The last cause is arguably the main source of trouble with
white smoke symptoms. In this condition, the oil can enter into the combustion
chamber through the piston ring gap when the engine is operating. This can be
due to two things ;
- Enlarged cylinder block volume, cylinder volume has been fitted with piston and piston rings conditions. If the volume is enlarged or in other words worn, then the piston ring widened and the gap is getting bigger.
- Wear piston rings, this is also the same case when the piston rings are getting eroded then the ring will widen and the gap is also getting wider.
Then, How to solve or fix this white smoke problem ?
img by vr6oc.com
Overcoming white smoke, must be done by replacing or fixing
the location of the oil leak. Therefore, to detect the location of oil leak
check the following components.
- Remove the PCV channel near the air duct after the filter, if there is oil droplet there is potential oil leaks from the breaker separator. To be sure, check up of the air ducts and if a lot of oil is on the air induction it means it causes it.
- The solution, you need to replace a set of PCV channels consisting of a hose and a separator.
- Next step, check the turbocharger area (if your car is equipped with turbo). By turning on the engine and pay attention to the sound from the turbo. Generally turbo that suffered damage will arise unusual sound.
- To be sure, remove the air output duct from the turbo. Here you can see if there are engine oil spills, if any leakage then that's the source of the problem.
- Check the engine compression pressure, you can do this check when the two components above are in normal condition. This check needs a special tool called compression tester available on authority workshops. Therefore it's good you bring car annoyance.
- If a compression is found to be lower than the normaly compression (every car have different compression rate), then there is a problem between the piston ring or the cylinder. for this problem requires engine disambling or your car need to stay overnight to resolve this problem, of course this can cost a lot.
- But if compression pressure is still normal, then there is one sector that is still the valve seal. To make sure about this, remove the intake manifold and see the intake hole. If it's full of oil crust then that's the problem. For this problem only need to replace the valve seal, but the replacement process is also quite complicated because it needs to disassemble the cylinder head. so do not be surprised if the cost to replace the seal is quite expensive.
So complete and super clear article to answer the question
"why my car have white smoke from exhaust ?” hopefully can be useful for
all of us and can add automotive insight for all of us.