Engine Oil
Melting Slicks
Joined: Mar 2001
Posts: 2,423
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From: western colorado colorado
Originally Posted by Michael A
You are better off in terms of engine wear with the 10W30, than the 5W30. The reason? The base stock of 10W30 oil has a higher viscosity than 5W30. A GM Research scientist told me that protection of highly loaded sliding surfaces is determined by the base stock of the oil. He also said viscosity index improver, which gives the oil a wider viscosity range, does not provide lubrication protection, so a straight weight or low range multiviscosity oil provides more protection. That said, this is less of an issue in modern engines, because many sliding surfaces, such as camshaft followers, now have rollers.
If you want fuel economy, go with the factory fill 5W30.
Michael
If you want fuel economy, go with the factory fill 5W30.
Michael
