Lubrication 7 - Oil-changing obsolete?
The question: 'are oil-changes a thing of the past?', is not that easy to answer. The recently extended oil-change intervals by the motor industry seem to support this thesis.
The above shown special oil-filter element is installed by a south-German company in motor-cars and in trucks. This could make the conventional oil-change unnecessary if the micro-fine paper filter, and perhaps a half a liter of engine-oil is replaced every 15,000 kms.
Because of the enourmous savings possibilies, the federal agency for environment instructed a testing laboratory to have a close look at this method. Of the three engines taking part in a 700-hour endurance test (63,500 km), one was equipped with a micro-fine special filter. Unfortunately, it did not score as well as the other two engines. It's piston-rings were stuck tightly together by a resinous, sticky substance and a piston-siezure threatened.
The fine-pored filtering is not the deciding factor, rather the improvement of the chemical properties which, together with the warming of the engine-oil, lead to an apparent ageing of the oil. Thus, the special-filter is less important in this method, than the changing of at least, a half a liter of engine-oil.
Nonetheless, there are indications of a possible lengthening of the changing intervals. Manual gearboxes, as a rule, are filled only once for the entire life of the gearbox. One truck manufacturer offers a doubling of the intervals from 40,000 to 80,000 km if a higher quality oil from the same company is used. Manufacturers double the length of the intervals for petrol engines to 50,000 km, and for diesel engines, as much as 100,000 km. There are of course, plausible reasons for short changing intervals. The sale of lubricants bring in about 40% of the earnings of garages and workshops. 09/12