"-Also, thicker is not better, no matter what your mechanic or engineer told you. 20W-50 has 40% more viscosity at operating temperature than 10W-30. This means that your engine has to work 40% harder just to move the oil around inside your engine. An engine with thick 'oil' produces significantly less power, uses more fuel, produces more emissions and runs hotter, all contributing to shorter engine life. A thinner oil can more easily and quickly be 'pumped-upí to the critical parts of the engine, takes less energy to move it around, helps the engine to produce more power, less emissions, better economy. And the engine will last longer too!"
So if this is the case, then thinner oils are pushed out of bearing surfaces easier than thicker oils. Then if you have a worn engine with bearing clearances pushing thier upper limits you want to run thin oil so you can have a low oil pressure and a thinner layer of oil on your bearings...and that will give you a longer lasting engine? This "master certified ASE tech" sounds like the same guy pushing Halogen fluid for the headlights. The same way the oil companys are telling you to change your oil every 3k miles.