All you need to know about motor oils

Motor oil is used to lubricate engines. That much is known, but high-performance oils perform many tasks to ensure the engine remains reliable and able to perform. This is why you should only use a motor oil that is specially customised to your Porsche. Regular oil changes are also necessary for it to retain its positive properties. Specifications can be found in your vehicle’s operating manual - or at our Porsche Centre.

The tasks of motor oils

Task 1

Task 1

Forming a film to ease movement of the surfaces in the engine. Lubrication is of particular importance to the cylinders and pistons, which must remain lubricated in order to prevent piston seizure. This film also protects against wear and tear and thus extends the life of the engine. In addition, fuel is saved through the reduction in friction.
Task 2

Task 2

Keeping the engine clean. Hot and movable engine parts are particularly prone to contaminants formed during the combustion process of fuels (including biofuels such as diesel) so are protected by a special additive in the oil. This additive binds contaminants in the oil and thus prevents damaging deposits building up in the engine.
Task 3

Task 3

Neutralising acids that are formed by combustion gases and unburned fuel in the oil. This prevents corrosion, especially in the bearings.
Task 4

Task 4

Heat dissipation. The oil cools many parts of the engine that the coolant does not reach.

Types of motor oils

The differences: in detail.
And in performance.

There are basically 3 categories of motor oils with varying properties:

Mineral oils are the longest known and used basic oils. They can be fairly easily and cheaply manufactured by distilling and refining crude oil.

Partially synthetic motor oils are created in a complex process and exhibit significantly higher quality especially in terms of resistance to ageing and temperature characteristics.

Synthetic oils are manufactured through chemical synthesis and can be specifically endowed with quality-enhancing properties. These oils get the very best out of your engine and are thus especially suited to high-performance vehicles.

Mono- and multigrade oils

Mono- or multigrade oil?
The types of oil and their properties.

Monograde oils dominated the market through to the 1970s. Every oil on offer had its own set viscosity and was marked as such.

Nowadays, multigrade oils are the most widespread engine oils. These are produced from a combination of low-viscosity base oils and special additives (eg. polymers such as polyester or polyisobutylene) so that their viscosity only slightly decreases at higher temperatures.

The advantages of multigrade oils.

Multigrade oils are better suited to cover a wide range of temperatures than ‘monograde oils’ due to only minor changes in viscosity. This means there is an optimal supply of oil within the engine at low and high temperatures and the level of lubrication during a cold-start is much higher. This also leads to less strain on the starter motor in cold weather and the level of lubrication is sufficient to withstand high exterior and engine temperatures.

SAE gradings

What do the numbers tell you about the area of application for a particular oil?

Multigrade oils feature 2 numbers in the SAE grading specifications (SAE: Society of Automotive Engineers) , e.g. 0W-40.

These indicate to which warmth and coldness ranges the engine oil is best suited. The letter ‘W’, means winter and how viscous (or fluid) the oil remains in cold weather - the lower the number, the better the viscosity of the oil. Therefore, 0 signifies an extremely viscous oil that can be used at low temperatures.

The second part of the details on viscosity (the number after ‘W’) indicates how viscous the oil is at high temperatures - the higher the number, the thicker the film of oil will be.

So 10 would stand for a very viscous oil that has specially been conceived for cold environments. Number 60 is to be used in extremely hot locations and is extremely thick in its normal state. 40 would therefore correspond to average viscosity and would guarantee optimal use even at high temperatures.