Brown residue near alternator??

I was right all along hahaha

 

Changing the belt won't stop it from getting rust on it. I suspect it got rusty from a pulley that touches the outside of the belt. I would find something else to worry about.

 

That story the dealer told you sounds like BS to me. I've owned a number of vehicles with serpentine belts and have never seen that. My bet would be on a bearing that got water in it and is rusting. If that is the case, you'll know soon enough. Whenever you change the belt spin by hand all of the pulleys and see if any are noisy or feel rough.

 

They will rust if there's exposed steel belts, you don't see that except on junked tires because nobody drives on exposed steel belts. All you have to do is look at a steel belted tire that's been damaged enough to expose the belts and has been sitting in the elements. The belts will certainly rust.

 

Rust on a smooth pulley surface could transfer to the back of the belt and make it orange like that

If a little water gets into the alternator and the brushes get wet it can spit orange dust out of the alternator case

 

Op never answered whether the truck is driven everyday or not. Rust developing on top of the idler pulleys is the obvious cause if it sits for a while. Either that or a bearing on one of the pulleys might be dry.

 

Model year 22 with 25 thousand miles in 1 year, that’s driven a lot . 1st post.

 

Post #58. He drives it everyday.

 

That was an awesome thread!

 

My 2021 with 63,000 miles has a lighter shade of the same color belt as OP. No color on alternator, a bit of a slightly different color dust coming out the AC compressor though. Nothing I'll worry about. When new I noticed the slight wobbling of the upper idler pully and told the dealer, dealer said it was normal, plus I have seen a Toyota factory notice detailing the same wobbling posted on this website. I'd bet we all have the wobbling and most have not taken notice of it.