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Is running-in oil used as the first fill in new cars from the manufacturer?

I am in the process of rebuilding an engine from the late 1940s. The recommendation, which I am following, is to use running-in oil for the first 500 miles to ensure a good bedding of the piston rings to cylinder bores due to the "cocktail" of oil additives. Different running-in oil is available for modern engines. Is this type of oil used as the first fill in new cars from the manufacturer?

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It used to be. Volkswagen proudly used to use recycled oil for this purpose and all engines were filled with it on the production lines. Then pressures from the fleets for extended oil change intervals led to factory filling with semi-synthetic and 'fully' synthetic 'Longlife' oil with variable service intervals that can be as long as two years and 20,000 miles. If an engine is run-in gently on these oils, the piston oil rings can fail to bed in sufficiently to the bores and the engines become oil users, gobbling up as much as a litre in 600 miles (1000 kilometres). Not sure how reliable this is, but I've read some advice to bikers to load their engines severely over the first few hundred miles to get the oil rings to bed in. This is opposite to the advice you will normally read. I must have been lucky because it's more than 10 years since I've run any car that used any significant amount of oil in 10,000 miles.
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