This question has been bugging me for quite some time. But, is there any particular reason the M62s have a coating on the outside? The M90s don't have it, so why is this? Is it because the M62 produces more heat? Let me know, I am curious.

So it won't corrode and get all ugly like the M90.

They didn't care about the M90 because it was hidden by a big cover. Notice the M90 nosedrive is coated?



Because it'* sticking out from the engine cover and not hidden. The M62'* cover doesn't hide it, so they pretty it up.

Bill...what happened to the thermal coating response that most of us expected to find in this post?

I could say that they had it because they needed everything they could get and since the M62 was substandard they prettied it up to polish a turd. That wouldn't be true though would it?

To the best of my knowledge and mostly from information that WillWren provided the reason is to help thermal transfer. The M90 didn't get the coating because of the cost and being that the M90 doesn't spin as fast, there isn't a need to cool any faster with speicalized coating.

I in fact have found that most if not all 96 M90'* were coated.

Hmmmm... So then my chipping of the coating around the bolt holes is fine? Just making sure.

Right..not a big deal overall.