I have seen recommendations for waiting until the manufacturer's first scheduled oil change or a minimum of 2,000 miles in new gasoline engines before using synthetic oil.
(My personal inclination is to get synthetic oil in there as soon as possible when an engine is new, but would not do so if I now see it as actually bad for the engine)
The only explanation I can think of is that conventional oil is more abrasive and will wear down the microscopic metal imperfections in the cylinder walls and rings, whereas synthetic is too slippery to permit the needed abrasiveness of conventional oil.
I agree with the manufacturer's recommendation. The 2000 miles on dino oil will allow the rings to seat properly in the cylinders and prevent oil consumption. Putting synthetic in right away will prevent proper break in and can cause issues later. Some of the more high performance cars like the Corvette comes with Mobil 1. However, these engines are individually run before shipment and are already broken in at the factory.
Yeah, what he said. You need a little friction during the break in period to properly seat the rings, UNLESS the manufacturer specifically states that this is not necessary. Some synthetics can be so slick that they don't allow this to happen, and you end up with glazed cylinder walls an an oil burning engine.
So, is it that "glazing" , and slickness of the cylinder walls, which is something that one would seem to want,(at least later in the life of an engine) is desirable only after the small (possibly) existing metal particles on the cylinder walls and rings have been rubbed off by the dino oil non glazing period at the start of the new engine use?
Running the factory fill conventional oil for the first 3,000-5,000 miles won't hurt at all, especially with today's SM-rated oils, but the recommendation against using synthetic from day one seems to have been obsolete since the mid-1980s, at the latest.
Below is a synthetic oil FAQ put out by Mobil about 10 years ago. Dial 1-800-ASK-MOBIL for more information.
Q: HOW OFTEN SHOULD I CHANGE OIL WHEN USING MOBIL 1?
A: A number of factors influence oil change frequency, including your driving habits, typical road conditions and environmental conditions. We recommend that you follow the oil and filter change frequencies shown in your owner's manual, especially during the warranty period. The excellent protection you get from Mobil 1 gives you the confidence to go the full length of the mileage or time frame recommended for changes by the manufacturer.
Q: WHY DOESN'T MOBIL CLAIM 25,000 MILE DRAIN INTERVALS ANY MORE?
A: Each auto manufacturer develops and specifies oil and filter requirements for their vehicles. Mobil respects their oil drain recommendations and does not want to put the consumer in a position that is in conflict with the auto manufacturer recommendations. While Mobil 1 has given excellent results in extended oil drain tests, we prefer to remain conservative with our oil drain recommendations. We recommend that you can go all the way to the maximum mileage or time shown in your owner's manual for oil changes when using Mobil 1.
This allows the reserve protection capabilities of Mobil 1 to cover unusual or unexpected driving conditions.
Q: WHAT VISCOSITY GRADE SHOULD I USE? WILL A HIGHER VISCOSITY GRADE (15W-50) PROVIDE BETTER PROTECTION?
A: Mobil recommends that you follow your engine manufacturer's recommendations as indicated in the owner's manual. For maximum wear protection and maximum fuel economy, use the lightest oil viscosity that is recommended by the engine manufacturer for the temperature range expected. Heavier oils lower fuel economy and rob horsepower. For normal driving conditions, 5W-30 and 10W-30 are the primary current recommendations of automotive manufacturers.
Q: DO I NEED TO FLUSH MY ENGINE BEFORE CONVERTING TO MOBIL 1?
A: No. There is no special preparation necessary when converting from conventional oil to Mobil 1. In fact, Mobil 1 is compatible with conventional oil should it be necessary to mix the two. However, the superior performance characteristics of Mobil 1 will be reduced by diluting it with conventional oil.
Mixing different types of synthetic oils is not recommended since different oils may be composed of different types of synthetic stocks. Change the oil and filter before changing from another synthetic oil to Mobil 1.
Q: WHEN CAN I START USING MOBIL 1? CAN MOBIL 1 BE USED IN AN OLDER VEHICLE?
A: You can start using Mobil 1 in new vehicles at any time. In fact, Mobil 1 is the factory fill for the Corvette LT-1 and LT-5 engines. One of the myths that persists about Mobil 1 is that new engines require a break-in period with conventional oil. Current engine manufacturing technology does not require this break-in period. As the decision by the engineers who design the Corvette engine indicates, Mobil 1 can be used in an engine from the day you drive the car off the showroom floor.
Mobil 1 can be used in older vehicles with high mileage on them. However, in older vehicles, if there is a problem with oil consumption or leakage, it may not be economically wise to convert it to Mobil 1 until such mechanical problems have been corrected.
Q: WILL THE USE OF MOBIL 1 VOID MY NEW CAR WARRANTY?
A: Absolutely not. Mobil 1 exceeds the API engine oil service requirements of all new car manufacturers. This includes both American and foreign-made autos. The only exception to this is the Mazda RX-7 rotary engine which recommends against using any synthetic oil.
Q: CAN I OR SHOULD I USE ADDITIVE SUPPLEMENTS AND/OR ENGINE TREATMENTS WITH MOBIL 1?
A: We DO NOT recommend the use of any additive supplements or engine treatments with Mobil 1. Mobil 1 has been formulated to greatly exceed the most severe industry and engine manufacturers' requirements. Using additive supplements will not improve the long-term performance of Mobil 1, and our tests indicated that use may actually degrade product performance. The American Petroleum Institute (API) and American Automobile Manufacturers Association (AAMA) have stated that "certified oils eliminate the need for supplemental engine oil additives."
Tests have shown that some additive supplements may significantly alter the performance and properties of any lubricant. In several cases, additive supplements have been detrimental to viscosity, storage stability and reduced protection against the formation of deposits.
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