In the early days of the motor car, the joy of owning one was sometimes dampened by the strict running-in regulations. The engine was provided with “running-in oil”, which was then replaced, together with the abrasion residue, by normal oil. Even afterwards, the oil-change intervals were very short. 20 oil-changes during the first 30.000 kms were not unusual, nowadays, modern Diesel engines can often do this mileage with the first filling of factory oil, not counting the topping-up.
Most drivers are not really concious of how much easier and more economical it has become. One is only aware of the pretty high oil prices and the increased oil-change amounts. Todays car-driver-generation has no idea, that earlier, rinsing with oil was carried out, even including the dismantling and cleaning of the oil pan, and this sometimes, with every second oil-change. The development of oil improvements and filter technology is a blessing, also for the environment.
Looking back, even the pressure circulation lubricationis not a necessity for running the combustion engine. Take e.g., the BMW Dixi which is a replica of the 1927 Austin Seven, only part of the engine was provided for by the oil pump. The rest was lubricated by oil-splashing. For this purpose, small tongues on the crankshaft which dipped into the oil bath were quite common.
On the other hand however, racing cars did not like oil pans at all. In this case, If the clutch permits it, the engine is mounted lower down and the oil pan is replaced by a sort of plate, from which the oil drips down and is suctioned up in the same manner as the dry-sump oiling system.
Thus, this type of lubrication allows larger amounts of oil to be used. Motor cars in racing trim can have, up to 20 liters of oil, an amount that that truck engines would laugh at. They carry this amount in their spacious oil pans alone, if they're not all-wheel drive vehicles and are to be used in particularly sloping terrain.
No oil-pressure circulation can endure air being sucked in. For this reason, after an oil change, some manufacturers recommend a starting procedure, without actually starting the engine. It's interesting to watch, how the oil pressure control shows the build-up of pressure only after the filter is filled. Actualy driving with too little oil must be avoided at all costs. Despite a perfectly functioning oil pressure control, damages can still occur. Nowadays, some assistance is provided by the multi-stage oil pressure control with interchanging red and yellow lights and a flashing mode.
One does not have to be a great fan of the mineral oil industry to establish that, particularly from 1995 onwards, through the increasing demands made on the oils, the oil change intervals have been enormously lengthened. A truck can now be run 100.000 kms when filled with certain oils. Manual-gearbox oil is almost never changed anymore.
The sensor development, running parallel to the oil development, may be particularly exciting. The same as with brake-fluid, which is now tested, and not rejected after a certain interval, this will be the case with engine oil. Not only will the oil level- and pressure be measured by sensors, also the viscosity at various temperatures, which supports the outspoken opinions that this is, through the intake of substances and oxidisation, recognisable by the viscosity. The result: Oil changing only according to necessity.