Definitions of Some Physical Characteristics of Lubricants

Classification of Engine Oils based on Efficiency Levels

1-API

American Petroleum Institute (API) categories efficiency levels of engine oils into two general classes. Petrol engine oils are represented by “S” (i.e. service station) and gasoline engine oils are shown by letter C (i.e. commercial). The efficiency level of every oil belonging to these two groups is shown by alphabetic letters after S or C letter.

2-ILSAC

ILSAC (International Lubricants Standardization Approval Committee).

3-CCMC

(Committee dec constrcteursd Automobile de Marche Commun) is Common MarketAutomobile Manufacturers Association. It is one of those entities which has developed classification system for engine oils.

In this system, oils are divided into three major petrol groups denoted by G (i.e. gasoline) with consequent numbers 1-5, D (diesel) with consequent numbers 1-5 as well as vehicles with diesel engines denoted by PD as well as numbers 1 and two. It should be noted that later on CCMC was turned into European Automobile Manufacturers' Association (ACEA).

Group 1

Petrol Engines

G1

G2

G3

G4

G5

Equivalent of SE in API

Equivalent of SF in API

Similar to G2 but with less viscosity

Equivalent of SG in API

Equivalent of SH in API

Group 2

Diesel Engines

Heavy Vehicles

D1

D2

D3

D4

D5

For light-weight diesel engines

For typical and/or turbo-charged heavy diesel engines

For typical and/or turbo-charged heavy diesel engines under difficult operation condition

Both levels are associated with diesel engine oils, similar to CE and CF4 levels in API system.

Group 3

Vehicles with Diesel Engines

PD1

PD2

4-MIL-L-…

US military is one of the oldest entities which has defined different levels of efficiency for oils. In this classification, MIL-L is an abbreviation for military lubricants and it is accompanied by certain numbers and English letters. In the case of fixed number, change of alphabetic letters signifies increased level of efficiency in a certain group.

API Classification for Gear Oils

API	Type of Servicing	Type of Gear and Transmission
GL-1	Medium operational condition with low pressure and vibrations	Circular angular gears Spiral gears, manual power transmission
GL-2	operational condition under load, temperature and speeds not matching GL-1	Helical gear of axel
GL-3	Relatively tough operation under load and definite speed	Circular angular gears, manual power transmission
GL-4	Tough operation with numerous vibrating movement and high load (high speeds and low torque or low speeds and high torque)	Hypoid gear in vehicles and other parts of vehicles, suitable for differentials and gearbox

Physical Characteristics of Gear Oil in Viscosity Classification (SAE J 306)

Character Degree

70W

75W

80W

85W

80

85

90

110

140

190

250

Density At 100C	Min (cst)	4.1	4.1	7	11	7	11	13.5	18.5	24	32.5	41
	Max (cst)	-	-	-	-	11	13.5	18.5	24	32.5	41	-
Max tem	For 150.000 CP (C)	-55	-40	-26	-12
Relative Standard Equivalent	(ISO)	22-32	22-46	46-100	100-150	46-100	100-150	150-320	220-320	320-460	680	1000

Properties of Gear Oils in Viscosity Classification (MIL-L-2105 E Standard)

Characteristic

Degree

75W

85W90

85W140

Viscosity At 100C	Min (cst)	4.1	13.5	24
	Max (cst)	-	24	41
Max temp. 150,000 CP	to get (Centigrade)	-40	026	-12
Max temp. groove	to generate (centigrade)	-45	-35	-20
Max Degree	Fire (Degree)	150	165	180