I just learned this lesson after hours of work and frustration. It all started with a little squeak that came about after running through some water. This is on my Dodge Ram (199K miles and runs great BTW
) but the same principle goes for any other vehicle. I knew the sound was coming from the left side of the motor so I pulled off the belt and inspected the alternator which was making a slight squeak when I spun it and the idler pulley which didn't seem great but was ok. So off to Autozone and get a new alternator under warranty - put it on, still no good. So I go get some belt dressing and spray the hell out of it. It quiets for a bit then starts making this horrendous noise. So today I'm back at it. I take off the serpentine belt and wash it along with the idler pulley. Still no worky. So I search the internet and find some info from a dude who accidently sprayed his with ArmorAll. I go out there and spray it with some silicon and sure enough, all is quiet.
I'm not new to working on cars but it's funny how you can not know something so simple. I just figured I'd pass along the info and save a person or two the frustration in the future.
Luckily I have another truck to drive now (see sig).
I'll put up pics later.
So go ahead and laugh. Apparently a friend of mine (that's a girl) even knew this.