Other things remaining equal, higher viscosity oil has higher film strength.
Other things never remain equal. PAO base oil, like Mobil 1, has higher film strength than petro base oil. Thus a 5W-20 PAO oil might lube as well as a 5w30 conventional oil. Ford and Honda approved 5W-20 has very tough specs...far tougher than a GF-4 5w30. That matters more than just the viscosity. The quality of the petro base oil is just part of the mix...5w30 might have better base oil than 10w30, or it might not, just have more viscosity index improvers that will soon shear. It depends on what quality product the oil maker wanted to put out.
The quality (cost) of the additive package is critical. Does Mobil 1 use a better quality add pack than, say, Wolf's Head or SuperTech or other cheap oil, still fully certified? Very likely.
You can not talk about just one attribute of oil unless all other properties of the oil are kept in mind. Talking about just viscosity is just hot air.
Ken
Other things never remain equal. PAO base oil, like Mobil 1, has higher film strength than petro base oil. Thus a 5W-20 PAO oil might lube as well as a 5w30 conventional oil. Ford and Honda approved 5W-20 has very tough specs...far tougher than a GF-4 5w30. That matters more than just the viscosity. The quality of the petro base oil is just part of the mix...5w30 might have better base oil than 10w30, or it might not, just have more viscosity index improvers that will soon shear. It depends on what quality product the oil maker wanted to put out.
The quality (cost) of the additive package is critical. Does Mobil 1 use a better quality add pack than, say, Wolf's Head or SuperTech or other cheap oil, still fully certified? Very likely.
You can not talk about just one attribute of oil unless all other properties of the oil are kept in mind. Talking about just viscosity is just hot air.
Ken