Lubricants, Oils, Greases, and Brake Fluids

What can happen if oils and greases are replaced improperly or with unspecified types?

Serious mechanical troubles

Solid lubricants like MoS₂ are used in which conditions?

. Dry or excessive vacuum

What is one role of engine oil in an internal combustion engine?

Prevent oxidation and corrosion

Which SAE grade is suitable for temperatures between -10°C and 10°C?

SAE 20W

Viscosity refers to:

The resistance offered by fluid to flow

Which API classification is CURRENT for gasoline engines?

SN

What does the first letter in API classification indicate?

Engine type

API Classification

American Petroleum Institute

Engine Oil – Roles

• To reduce wear caused by bearings, etc.

• To reduce heat generated and escape through the clearance between the piston and cylinder.

• To prevent oxidation and corrosion in the engine by sulfuric acid produced by the gas and water resulting from combustion.

SAE Grade | Temperature Range (°C):

SAE 10W → -20 to 0

SAE 20W → -10 to 10

SAE 30 → 0 to 30

SAE 40 → 10 to 40

SAE 50 → 30 to 50

Low viscosity →

thin oil (winter)

High viscosity →

thick oil (hot temperature)

Green

General purpose grease

Smooth texture, water resistance, oxidation stability

Blue

General purpose grease

Smooth texture, water resistance, oxidation stability

Red

General purpose grease

Smooth texture, water resistance, oxidation stability

Gray Chassis

grease

Contains MoS₂, good load capacity

Black

Chassis grease

Contains MoS₂, good load capacity

Brown

Chassis grease

Contains MoS₂, good load capacity

Yellow

Barium grease

Water resistance, oxidation stability

Orange

Barium grease

Water resistance, oxidation stability

White

Food grade grease

Non-toxic, no industrial additives

Purple

Synthetic high-performance grease Extreme pressure, high temp, long life

Grease

is like a sponge soaked in oil—it holds lubrication in place and is ideal for parts that don’t get frequent maintenance.

is a semi-solid oilv lubricant manufactured by mixing a mineral oil with various kinds of metallic soap.

Oil

flows freely and is better for systems that need continuous lubrication and cooling, like engines or gearboxes.

Brake Fluid

Function: Transmits pressure from master cylinder to calipers

is a medium for transmission of the pressure generated in the brake master cylinder to each wheel cylinder or brake caliper.

Glycol-based brake fluids include:

DOT 3, DOT 4, DOT 5.1

DOT 5 brake fluid is

Non-hygroscopic

ATF (Automatic Transmission Fluid)

• refers to a transmission fluid used in vehicles with automatic transmissions.

• It is typically red or green to distinguish it from other fluids in the vehicle.

• used in vehicles with automatic transmissions and in some modern manual transmissions.

API S Gasoline engines are classified under Category

SPARK IGNITION 

API C Gasoline engines are classified under Category

Compress