- 11/13/2024
- 4min
What are the differences between various motor oils?

What is the significance of the viscosity of a motor oil?
The viscosity indicates the flow resistance of an oil or how viscous it is. Two numbers are used for the correct designation. The first number is always marked with a “W”, which stands for “winter”. The number thus indicates the lower operating temperature of the motor oil. The number stands for the fluidity at an oil temperature of 100 °C, because motor oils are naturally more viscous at low temperatures than when heated.
Here the rule is: The lower the number is, the thinner the oil. For example, a 5W-40 oil is thinner at a low cold-start temperature than a motor oil with a viscosity of 10W-40. A 10W-30 is thinner than a 10W-40 at an oil operating temperature of 100 °C.
However, viscosity alone is not a quality characteristic.

Why are motor oils becoming thinner and thinner?
The thinner a motor oil is, the less force the engine needs to apply to pump it through the circuit. This reduces fuel consumption, which supports the constant efforts of the car manufacturers in reducing vehicle emissions.
The thinner a motor oil becomes, the more important the role of the additives. In the past, the base oil was the most important performer in motor oil, but today it is the additive packages. Almost a third of modern oils consists of additive packages. Only these ensure cleaning, corrosion protection, cooling and lubrication for the extremely thin-bodied oils. The actual oil is often only the carrier fluid of the additive packages.
Which oil for which vehicle?
When selecting the right motor oil, it is primarily crucial that the specifications specified by the manufacturer are met. There are now more than 50 different manufacturer approvals. Before buying a motor oil, it is therefore essential to take a look at the vehicle manual and check what requirements the oil must meet.
With our oil guide, you can find the right motor oil for your vehicle in just a few seconds.