I know a guy who used top work in one of the Buick labs here in Flint. About five years ago they performed a major oil test with 10 different brands of oil. The idea was to match the correct oil with the correct driving habits. But they also wanted to compare synthetic oils with petroleums. In a nutshell here's the most fascinating part of the study.
They took a brand new 3800 and filled it with 10W-30 Mobile One and and fired her up. Every 5,000 miles they'd stop the engine and change the oil filter. They'd only then top off what little drained into the grate. After 100,000 miles they had performed no complete oil changes, but dug a sample out of the oil pan and analzyed it. It had zero sign of breakdown.
