| Questions - Answers
LUBRICANTS : |
 | What
is a lubricant ? |
 |
A lubricant is a mixture of one or several basic oils with additives which provide
additional properties or allow oils to keep their characteristics. |
 |
|
What
are the main functions of a
lubricant ? |
| | A
lubrication oil is used mainly for :
 | minimising
the mechanical wear caused by surface friction while moving . |
| removing
heat | | preventing
deposit formations | | eliminating
carbon residues and deposits. | |
| |
| What
is a mineral oil, a synthetic oil and a semi-synthetic oil ? |
|
| A
mineral oil is made up of molecular medium and high-weight hydrocarbons coming
from the refining of crude oil. | | An
oil is called synthetic when the basic oil is obtained through chemical reactions
of several components under controlled conditions. Basic synthetic oils can be
classified into three categories : . Synthetic hydrocarbons
. Organic esters
. Other synthetic oils |
|
A
semi-synthetic oil is
a mixture of mineral and
synthetic basic oils in
which the proportion of
mineral oils exceeds 15%. |
|
| |
| What
is a multigrade oil and a monograde oil ? |
|
|
A multigrade
oil is an oil that
can be used in winter
as well as in summer.
It is characterised by
two figures : the first
is followed by the letter
W ( Winter) which is for
cold temperatures, the
second figure is for hot
temperatures. Example
:5W40, 15W40. |
| A
monograde oil is an oil meant to be used in winter or in summer depending
on its viscosity grade . Example :SAE 10W, SAE 40. | |
|
| Is
it possible to mix oils having the same quality but different brands ? |
| Generally
speaking, it is not recommended to mix two oils of different origins because such
a mixture provides lower performances than those provided by the two oils used
separately. Formulation synergies may be impaired mainly for synthetic products.
|
| |
| What
is the meaning of the information on the package ? |
|
| SAE
: Society of Automotive Engineers, is an institution which defines the grades
and limits of viscosity | | | SAE
x W y where x and y are two figures representing the cold viscosity
grade (x) and the hot viscosity grade (y) . | | API
: American petroleum institute : is an institution which classifies lubricants
according to their performance. Two API specifications are to be considered for
lubricants :
Sx for gasoline engines
Cy for diesel engines
Where
x and y are progressive letters showing successive updates. |
| MIL
-L : American military specifications introduced by the Army in order
to define the requirements of army cars
There are two standard specifications
MIL-L-46152 x and MIL-L-2104 y, where x and y are two progressive letters showing
successive updates. | | ACEA
: Association of European Car Manufacturers defining the performances of oils
adapted to European manufactured cars. Three sequences are to be identified: |
| | -Sequence
A : for gasoline engines
-Sequence B : for diesel
engines and light commercial
vehicles
-Sequence E : for diesel engines and heavy commercial vehicles
A, B and E are followed by a figure showing the level of severity |
|
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