I don 't agree or disagree with COBRATOO but as an engineer, I am questioning, or better put, I am curious about, Honda's decision to switch viscosity, as pointed out by GMCC. Warranty will not be voided by switching viscosity but fuel economy may be, but by how much and at that what cost (shorter or longer engine life, smoother/harsher operation, etc)?
From what I have read, the switch occurred only to improve the corporate average fuel economy unless key elements have been addressed with regard to the engine that I am not privy too.
My main concern stems from the notion that if you put a thin oil such as 5W20 or 0W20 into i.e., a boxer engine (subaru or porsche) that engine will chew up that oil and many Subaru boxers are only 2.5L H4 design, producing only 170 Hp with very similar amount of torque (turbo ones produce more as do the 3.6L H6 ones) but still, we are only dealing with 2.5L engines. So when I see 0W20 oil, synthetic or dyno, in a V6, and I do not undermine Honda's engineering, I just wish to know, is this an attempt at lowering fuel consumption? if so, at what cost? Or is this a genuine message from Honda saying, "we have perfected this engine so much so that you can use the same oil as some 3 or 4 cylinder engines which offer substantially less output".
