13.1. Engine oil
At an engine oil choice first of all it is necessary to be guided by recommendations and manufacturer requirements to quality and the manufacturer of engine oil.
The modern engine oils consisting of base oils and the picked up set of additives, are divided into two principal views:
– Mineral (received by distillation from oil) – their viscosity strongly depends on temperature. Various additives which, in turn, quickly enough collapse because of high mechanical and thermal loadings are applied to stabilisation of properties, reducing oil service life;
– Synthetic (received by chemical synthesis) – possess high uniformity and stability of properties. Remain more liquid on a frost and more dense in a heat, burn down in the engine less, form less adjournment, have больший service life.
Synthetic oils do not destroy engine epiploons, however at their use leak occurrence through the worn out epiploons owing to большей fluidity of synthetic oils in comparison with the mineral is possible.
Service life of synthetic oils only ненамного, than mineral. Fast dimness of oil testifies only to its good washing properties and the polluted system of greasing.
Intermediate position is occupied with so-called semisynthetic oils. They are made on a mineral basis, but with additives of synthetic components, therefore on quality come nearer to synthetic oils, but is much cheaper than them.
One of the basic properties of engine oil – its viscosity which defines a temperature range of application of engine oil. At low temperature of air engine oil should have low viscosity to provide start-up of the engine and engine oil receipt to its knots. At a heat engine oil should be more viscous to support in system of greasing demanded pressure of oil. On value of viscosity engine oils divide into three kinds:
– Winter – thanks to low viscosity provide start-up of the engine and greasing of the basic knots at negative temperature of air;
– Summer – thanks to high viscosity provide greasing of details of the engine at an air heat;
– All-weather – at low temperature of air possess viscosity of winter oils, and at high – viscosity of summer oils.
Categorically application of engine oils is forbidden:
– Not intended for petrol automobile engines;
– With inappropriate operational characteristics;
– Not corresponding to a season on viscosity (on classifications SAE).