It is ok to increase the viscosity and if you look at oil manufacturers in other countries, say Aus, they recommend up to 40 for your engine.
OM even says on the back that a higher viscosity oil is better under certain conditions, so no, there won’t be a kabum or anything harmful happening.
My engine requires 5w-30 and I don’t think I’ve used the recommended oil more than 3 intervals. Everything other than the recommended oils and my UOA’s posted on the forum support the view that there are no ill effects.
I stopped paying for UOA as they were just repeating themselves. For the past 30-40k, maybe even 50k, I’ve been using either Pennzoil 0w-40, M1 0w-40 and now I’m using Castrol 5w-40. I have a year of M1 and Castrol oil in the garage.
Mileage is still great and pretty quiet too.
Sleep well. Do not worry. Your engine is designed to handle 5w-30 and higher.
