If it's a lack of flow and lubrication due to design/manufacturing issues, depending on the severity of how much flow is cut down from the flaw, I doubt the viscosity is going to matter much when the oil is at operating temperature due to the PD pump.Sure design and/or manufacturing error causing lack of lubrication is a factor, but there are lots of these engines with 200K+ miles. The issue is no one buys a new designed engine and knows there are going to be issues. So, would going to a 5w30 benefit avoid oil related failures?
On the other hand, in a case like that, it's possible most of the lack in lubrication occurred during very cold start-ups if the oil pump hits pressure relief quickly and stays in relief for quite awhile. In that case, a lower W viscosity may help.
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