The best-known lubricants used in a car are engine oils and transmission oils. They are used in different places in the car and fulfil different functions.
Engine oils are used directly in the combustion engine, where they protect the moving parts from wear so that the engine can perform its service for a long time. Engine oils are more heat-resistant than transmission oils, as they are permanently exposed to high temperatures when driving. However, the combustion processes in the engine cause the oil to become increasingly contaminated over time. It must therefore be changed at regular intervals in order not to lose the wear protection and damage the engine.
In transmissions, things are not nearly as hot. Here, transmission oils take on the function of wear protection, corrosion protection and friction optimisation in order to secure power transmission in the long term and to improve driving comfort with smooth transmission shifts. Transmission oils do not have to be changed as often as engine oils. But recently since the significantly increased popularity of dual-clutch transmissions, the transmission oil has also become more important to drivers. Here, change intervals of around 60,000 km are intended. This is due to the friction processes when shifting transmissions in dual clutches. The transmission oil thermally degrades much more than in a manual gearstick. And the degradation products cause the oil to age more quickly.