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Timing, Check > < Oil Pressure, Check

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Oil Consumption, Measure

General

The term "oil consumption" of an internal combustion engine refers to the amount of oil that is consumed as a consequence of combustion. Oil consumption should under no circumstances be confused with oil loss caused by leaks in the oil pan, cylinder head cover, etc.

The task of the engine oil is to:

1. Separate surfaces that slide on one another with an oil film, i.e. prevent dry friction;
2. Conduct the heat produced by friction away;
3. Conduct combustion residue away.

These tasks necessitate the consumption of a certain amount of oil, i.e. the expectations of many who claim that further development of the internal combustion engine will lead to an engine that does not require oil, are absolutely nonsensical. The oil consumption is however influenced by external operating factors, driving style and manufacturing tolerances. Care should be taken that the oil level does not drop below the "MIN" mark on the dipstick and does not exceed the "MAX" mark on the dipstick.

As oil consumption is a technical necessity, indications that an engine is not consuming oil mean that we can conclude that the oil is being diluted by special operating conditions. Frequent cold starts, driving when over-cold, etc. result in the oil flowing back to the oil pan containing fuel particles and condensation, and thus becoming "diluted"; this can lead to the incorrect supposition that the engine is not consuming any oil at all. Oil diluted in this fashion lacks lubricating power and may lead to engine damage if the prescribed oil change intervals are not observed. The main causes for oil dilution are driving in mainly urban traffic and frequent driving at too low engine speeds when the engine is cold.

The oil consumption first begins to stabilise after operating for a few thousand kilometres; therefore, measurements of the oil consumption only become realistic after about 7500 km/4000 miles. Before measuring the oil consumption, ensure that the engine is not losing oil due to a leak.

Note:   The oil dipstick can only be used for checking and not for measurement. The engine must always be switched off for at least 2 minutes before the oil level can be checked. If, after an oil change, the maximum engine oil filling does not match the maximum level mark on the dipstick, this can be attributed to manufacturing tolerances.

All information regarding the permissible engine oil consumption and filling quantities are included in the Owner's Manual.

Measuring Method

1. The check is carried out with the vehicle on a horizontal surface with the engine at operating temperature (engine oil temperature min. 80 °C / 176 °F).
2. Drain engine oil immediately after switching off engine – draining time approx. 30 minutes (this value was determined experimentally).
3. The drained engine oil quantity is measured in a measuring container 1) and fresh oil added to the maximum engine oil filling quantity, minus the volume for the engine oil filter that has not been changed.
4. Using this amount of engine oil, the customer should drive at least 1000 km/625 miles without of course topping up the engine oil (the driver should keep to his normal routes and driving styles).
5. The procedure described above (points 1 to 2) is then repeated with exactly the same time for draining engine oil.
6. The quantity of engine oil "missing" from the measuring container is the engine oil consumption with respect to the distance travelled.
7. The oil consumption is calculated as follows:

filled oil quantity (l) – drained oil quantity (l)

x 1000 = oil consumption (I/1000 km)

distance actually driven (km)

1 ) Measuring container with a capacity of at least 6 litres and scale.
Related Literature Units
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Timing, Check > < Oil Pressure, Check