The main indicator of quality of engine oil is its viscosity. It is necessary to fill the engine with oil with the optimum viscosity which value depends on a design, an operating mode and degree of wear of the engine, from ambient temperature and other factors.

Now as conventional classification of automobile engine oils by the SAE J300 standard (Society of automobile engineers of the USA) is. Viscosity of oil in this system is expressed in conventional units — degrees of viscosity of SAE VG. Distinguish the following standard ranks of viscosity on this system:

SAE 0W, 5W, 10W, 15W, 20W, 25W (a winter row);

SAE 20, 30, 40, 50, 60 (a summer row).

All-weather oils unite in themselves properties of oils of both ranks. They have the combined designation, for example, SAE 10W-40.

Number of all-weather oils: SAE 0W-20, 0W-30, 0W-40, 0W-50, 0W-60, 5W-20, 5W-30, 5W-40, 5W-50, 5W-60, 10W-30, 10W-40, 10W-50, 10W-60, 15W-30, 15W-40, 15W-50, 15W-60, 20W-30, 20W-40, 20W-50, 20W-60.

Fig. 1.52. Oils for petrol engines

Summer oil has sufficient viscosity to provide reliable greasing at high temperature, but it too viscous at low air temperature therefore engine start-up is at a loss. Low-viscous winter oil facilitates start-up of the cold engine at low temperature, but does not provide its greasing in the summer when the oil temperature in the engine exceeds 100 °C. Therefore the all-weather oils which viscosity depends on temperature less now are most widespread. On

Fig. 1.53. Oils for diesel engines

fig. 1.52 and 1.53 temperature intervals of use of engine oils are given. It is recommended to apply all-weather oils 15W-40, 15W-50, 20W-50 to engines of Volkswagen Passat cars.

The average consumption of oil on 1000 km of run of the car makes about 1 l.

Fig. 1.54. Index of level of engine oil and maslonalivny mouth: 1–index of level of engine oil; 2–maslonalivny mouth

Level of engine oil is checked on the car being on an equal surface, later 5 mines after an engine stop. For this purpose take out the index 1 (fig. 1.54) of level of oil (щуп), wipe it rags, again completely insert and then again take. Level of oil should be between «MIN» and «MAX» marks (see fig. 1.54 ). The volume of engine oil corresponding to a difference of levels between labels "MOVE" and "MIN" on the index of level of oil, makes about 1 l.

At a dolivka and replacement it is necessary to use the oils of the same brand made on the same basis. At change of brand of oil it is necessary to wash out system of greasing of the engine special solution. Oils of one brand with an identical basis, but various viscosity can mix without restriction.

It is necessary to replace engine oil through each 15 000 km of run for the petrol engine and through 7600 km — for diesel. In case of infrequent operation of the car to replace oil follows not less often than 1 time a year together with the oil filter.

For plum of oil execute the following operations:

– establish the car on a horizontal surface or on the lift;

– weaken a stopper of a drain opening, having placed under it capacity for oil;

– unscrew a stopper;

– wait, while oil completely will merge;

– clear a stopper rags, establish on it new consolidation;

– turn and tighten a stopper of a drain opening.

For replacement of the oil filter execute the following operations:

– establish capacity for oil under the oil filter;

– unscrew the oil filter;

– wait oil plum;

– clear rags a flange of installation of the oil filter;

– to grease with new oil laying of the established filter;

– establish the new filter.

PREVENTION It is forbidden to pour oil above a label "MOVE" is leads to failure of consolidations of a cranked shaft and catalytic converter of the fulfilled gases. If the fulfilled engine oil contains metal shaving, urgent diagnostics of the engine and, as a rule, its major maintenance is necessary.

Fresh engine oil is filled in through a mouth 2 (see fig. 1.54 ), located on a cover of a head of the block of cylinders.