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

Now as conventional classification of automobile engine oils by the SAE J300 standard (Societies 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 (winter row);

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

All-weather oils unite in themselves properties of oils of both rows. They have the combined designation, for example, of 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 the low air temperature therefore launch of the engine is at a loss. Low-viscous winter oil facilitates launch of the cold engine at a low temperature, but does not provide its greasing in the summer when oil temperature in the engine exceeds 100 °C. Therefore now all-weather oils which viscosity depends on temperature less are most spread. On

Fig. 1.53. Oils for diesel engines

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

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

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

Level of engine oil is checked on the car which is on a plain surface 5 min. later after an engine stop. For this purpose take out the index of 1 (fig. 1.54) of level of oil (probe), wipe it with rags, again completely insert and then again take. Level of oil has to be between the marks "MIN" and "MAX" (see fig. 1.54 ). The volume of engine oil corresponding to a difference of levels between tags "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. When changing brand of oil it is necessary to wash out the engine lubrication system special solution. Oils of one brand with an identical basis, but various viscosity can mix without restriction.

Engine oil needs to be replaced through each 15 000 km of a run for the petrol engine and through 7600 km — for diesel. In case of infrequent operation of the car it is necessary to replace oil at least 1 time a year together with an oil filter.

For discharge of oil execute the following operations:

– install the car on a horizontal surface or on the elevator;

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

– turn off a stopper;

– wait until oil completely merges;

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

– turn and tighten a stopper of a drain opening.

For replacement of an oil filter execute the following operations:

– establish capacity for oil under an oil filter;

– turn off an oil filter;

– wait for oil discharge;

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

– to oil new laying of the installed filter;

– install the new filter.

PREVENTION It is forbidden to pour oil above a tag "MOVE" – it leads to failure of consolidations of a bent shaft and catalytic converter of the fulfilled gases. If the fulfilled engine oil contains metal shaving, then urgent diagnostics of the engine and, as a rule, its capital repairs 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.