FUNCTION OF MOTOR OIL
If the engine is the heart of a car, then the motor oil is its blood. But not all oils are the same. With the continuous development of engines, the requirements made of oil have also increased. Oil must now be capable of much more than just lubricating and cooling: It must function even at high temperatures and pressures; it must clean the engine from combustion residue, grit, acids, water and fuel particles; it must protect the engine from corrosion and maintain its own density. Modern engine oils are high-tech liquids designed specifically for use in certain car models, practically tailor-made replacement parts.
Therefore you should imperatively use the right oil. Your driver manual clearly says what kind of oil your motor needs. If you use other motor oils than those specified you will experience a number of disadvantages, such as:
Loss of manufactures warranty,
Incresed fuel consumption,
Increased engine wear / decreased engine life
Risk of breakdown, and damage to catalytic convertor.
TRANSMISSION & GEAR OILS
OIL FOR MANUAL AND AUTOMATIC GEAR BOXES
Depending on whether there is a manual gearbox or an automatic gearbox the vehicle needs different gearbox oil. The standards vary and so also the gearbox oils are different from each other.
The main purpose of oil in manual gearboxes is to lubricate. Because power is transmitted by axles, there is not much more to do for the oil. In automatic gearboxes the oil has to do a lot more. Power is transmitted not by axles but by the oil itself, so it needs a precisely defined friction coefficient. If it deviates from this coefficient the automatic gearbox doesn’t shift gears correctly or even doesn’t shift gears at all.
That’s why you should closely regard the manufacturer’s specifications.
So pouring manual gearbox oil in automatic gearboxes will always go wrong. Conversely, most automatic gearbox oils will do their job in manual gearboxes – but not all. So you better should not confuse the two oil grades. You are on the safe side if you closely follow the instructions in your driver manual.
GREASES AND OTHERS
Grease is a semisolid lubricant. Grease generally consists of a soap emulsified with mineral or vegetable oil. The characteristic feature of greases is that they possess a high initial viscosity, which upon the application of shear, drops to give the effect of an oil-lubricated bearing of approximately the same viscosity as the base oil used in the grease. This change in viscosity is called shear thinning. Grease is sometimes used to describe lubricating materials that are simply soft solids or high viscosity liquids, but these materials do not exhibit the shear-thinning properties characteristic of the classical grease. For example, petroleum jellies such as Vaseline are not generally classified as greases.
Greases are applied to mechanisms that can only be lubricated infrequently and where a lubricating oil would not stay in position. They also act as sealants to prevent ingress of water and incompressible materials. Grease-lubricated bearings have greater frictional characteristics due to their high viscosity.