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Frequently Asked Question

Group I base oils are the traditional older base oils created by a solvent-refining technology used to
remove the weaker chemical structures or bad actors (ring structures, structures with double bonds)
from the crude oil

Group II base oils are created by using a hydro treating process to replace the traditional solvent-
refining process.  Hydrogen gas is used to remove undesirable components from the crude oil.  This
results in a clear and colorless base oil with very few Sulphur, nitrogen or ring structures.

Group II oil when refined, becomes clear like water. This is called group II Premium base oil. Chevron
has over 100 years of experience in producing fuels, lubricants and base oils and introduced
ISODEWAXING® catalyst and technology, a radical new refining process that produced water-white,
chemically pure base oils from conventional feedstock.

Crude petroleum goes through a process of refining to make Mineral oil. During the process, naturally
produced waste and unwanted hydrocarbons are removed. Mineral oils are ideal for older vehicle models.

That being said, mineral based oils flow through the engine circuit more slowly. This results in increased
fuel consumption and impacted vehicle performance. Mineral oils also need to be changed more
frequently than synthetic oils.

Synthetic engine oils are a product of complex chemical transformations that are performed either directly on crude petroleum extracted by drilling, or using preselected molecules. The difference with mineral oils resides in the transformation process as it goes through more complexed refining process.

A multigrade oil is an oil whose properties have been enhanced to reduce its viscosity with temperature.
Thereby, compared to monograde oil, multigrade oil is more fluid at low temperatures and thicker at
high temperatures.

Multigrade oils are engine oils which can be used in a wide temperature range. The oils are flowable in
cold conditions and can lubricate the engine reliably. When heated, the oil does not become too thin
and remains resistant to loads. This means that the lubricant film does not break off even at peak
temperatures in the engine.

W is oil grade represents winter in regards to its temperature. The multigrade oils can be recognized by
the typical SAE classes on the labels such as 5w30. The first number "5w" stands for winter suitability up
to a certain temperature and the second number "30" for a specific viscosity at 100 °C.

Viscosity index is a dimensionless number that represents how the viscosity of a fluid changes with
temperature. The greater the viscosity index (VI), the smaller the change in fluid viscosity for a given
change in temperature, and vice versa. Thus, a fluid with a low viscosity index will experience a relatively
large swing in viscosity as temperatures change. High-VI fluids, in contrast, are less affected by
temperature changes.

Monograde oils are designed to be used within a defined temperature range. The monograde oils are
classified by the thickness (or viscosity) of the oil. The intention is to ensure that the oil will cycle as
required under specific operating conditions. Monograde oils are defined by a viscosity rating at 100°C
only. The viscosity rating at low temperature is not considered or specified. Limits of the viscosity values
at 100°C for standard mono-grades (SAE 30, SAE 40, SAE 90, etc) are classified by the SAE International.

API stands for American Petroleum Institute. This organization sets performance standards for each
category set in which lubricant manufacturers must adhere to formulate commercial and automotive
engine oil products. For example, the latest API category for commercial engine oils is API CK-4. API
categories before API CK-4 would be considered “backwards compatible” which means that a product
that meets API CK-4 could be used in place of say a previous category such as API CJ-4 or CI-4 Plus.

You are correct in assuming that water is the best heat-transfer fluid. So, if you don’t need the freeze,
and boil-over protection, why spend the money? The reason is that most modern engines need the
additional boil protection that is provided by the base fluid. Also, water, just as a glycol/water mixture, is
very corrosive; it causes rust. It will actually attack the metal components in your engine. A coolant will
also provide the all-important corrosion protection. It will prevent the metal components in your cooling
system from rusting.

This purely depends on the nature of the product as every product has different properties. The lead
time is communicated to Chevron Pakistan and a tentative date is given to our Supply chain department.