Engine Oil Information
Why Motor Oil is Important
Motor oil is a lubricant that keeps the hundreds of
moving parts in your car's engine from rubbing up
against each other and causing wear.
• It reduces friction,
• allows your car to start easily,
• keeps the engine clean,
• blocks any little gaps between the piston ring and
the cylinder walls,
• prevents rust and corrosion.
• It also keeps any foreign particles away from engine
Viscosity is the ability of a liquid to be poured.
Multi-grade Motor Oil
Multi-grade oil has two numbers and a letter, for
example 10W - 30. The first number refers to
the low-temperature viscosity, or the viscosity
of the oil when the engine is cold. The second
number refers to the viscosity of the oil when
the engine is at operating temperature.
A higher number viscosity rating will not flow as
easily as a lower number, so a lower number is
better for colder temperatures.
API Service Ratings
• SM - For all automotive engines presently in
use. SM oils are designed to provide improved
oxidation resistance, improved deposit
protection, better wear protection, and better
• SL - For 2004 and older automotive engines.
• SJ - For 2001 and older automotive engines.
Choosing the Right Motor Oil
• Mineral oils are based on refined crude oil
that comes from dear old Mother Earth.
• Synthetic oils are designed to reduce wear
and tear on gears, reduce oil oxidation and
sludge formation, and allow for extended
• Semi-synthetic, sometimes called premium,
which is a blend of the two.
When to change engine oil
Eventually motor oil breaks down in the engine.
Contaminants accumulate cause oil to lose viscosity.
Additives in the oil are used up in normal operation of
the vehicle, after which corrosion and oxidation occur.
Some experts recommend changing the engine oil
every 5,000 km (3,000 mi) or every 3 months.
Follow your owner’s manual.