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2. FUNCTIONS OF LUBRICATION
1) Lubrication
It creates a viscous barrier between moving parts that reduces friction, which means less heat
and longer life for those parts. As a lubricant, oil must maintain a protective film to prevent metal-
to-metal contact. It must be fluid enough to allow easy starting and to circulate quickly through
the engine, yet remain thick enough at higher operating temperatures and speeds to provide
adequate lubrication.
2) Cooling
Combustion heat and friction energy must be removed from the engine in order to prevent its
overheating. Most of heat energy is taken by the engine oil.
Clean oil passages, proper viscosity and low contamination provide sufficient flow rate of the
engine oil and effective cooling.
3) Sealing
It helps to seal the space between the pistons and the cylinder walls so that compression is more
effective and power is not lost during combustion.
4) Anti-corrosion
As a corrosion inhibitor, oil coats internal engine parts to prevent surface rust on the inside of the
engine which can be caused by blow-by products and water formed in combustion. It must also
be capable of neutralizing the acids that are formed by combustion blow-by and oil oxidation at
high temperatures.
5) Cleaning
The small particles of dirt or other contaminants are suspended in oil and carried away to be
filtered out. As a detergent, engine oil must be able to gather and suspend dirt and other
contaminants until the oil can leave them as it passes through the filter and returns to the internal
engine environment.
15-490000-00
E. Cautions
Use only specified Engine Oil (approved by MB Sheet 229.51) for CDPF. -
Use only specified engine oil (Low Ash Oil) ▶
The vehicle equipped with CDPF should use specific engine oil to improve the engine performance
and fuel economy, and ensure the service life of CDPF. -
Issue with normal engine oil ▶
Sulfur, one of the contents of engine oil is burned and generates soot that is not regenerated by the
DPF. This remains on the filter as ashes and keeps accumulating. Eventually, this ashes will block
the filter. -
Benefit for specified engine oil ▶
Minimized the sulfur content of engine oil which reduces the service life.
Improved fuel economy and emission level of CO2 with high performance and low viscosity.
Increased service life of engine oil with high resistance to temperature. -
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Problems when using unspecified engine oil ▶
The service life of filter may be reduced by 30% or more by the ashes accumulated on the filter.
The fuel economy may be reduced because of engine rolling resistance, frequent regeneration of
DPF. -
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These problems are also caused by oil with high sulfur content, such as tax exemption oil and
heating oil, etc. *
