Brown residue near alternator??

you've found the long lost Rust belt, you're gonna be famous

 

In the photo showing the upper radiator hose, why is the clamp mark on the hose, and the clamp, in different locations? Has the upper rad hose been removed for some reason?, is it slowly leaking coolant water on the belt? Have you checked to see if the belt is wet just after a drive long enough to get the coolant up to temp?

 

Disregarding the dust buildup, Just here to say I have a 2018 and my belt is still original and it’s black… I don’t know all the ins and outs of drive belt construction but it looks likes somethings up with the belt. I’d remove and replace belt and give the idlers a spin and see how the bearings are doing. Does the brown stuff wipe off the belt?

 

still under warranty, take it in

 

Just think of it was the alternator how would it apply the red residue on the outside surface of the belt????

 

Just a food for thought . So some serpentine belts has steel layer/fabric. https://youtu.be/RCejWrzx3Fk?si=rYSLvBb4mG9Ati4b

 

It’s a Toyota, everything you place on or in it will rust.

 

So true

 

ok mr engineer why dont tires rust

 

I don’t know ha ha

 

He's a belt engineer, NOT a tire engineer. BIG DIFFERENCE!

 

Bearing is shot…take the belt off and spin it to confirm.

 

I am in the idler pulley camp. What are your driving patterns? Does the truck regularly sit for a few days without being driven, or has it sat for a longer period of time? Surface rust may form on the idler pulleys (like it does on the surface of brake rotors after just a couple of days) and then transfer to the belt. I would change the belt and clean stuff up. Actually, I'd probably just clean stuff up and not worry about it unless the belt started deteriorating or I heard some funny noises.

 

My 2019 Tacoma with 90,000 miles looks exactly like that. From research I have done it is grease leaking out of the worn out bearings on the idler pulleys or the belt tensioner. Just checked mine and they all need replaced. Not to the point of a squeaking sound yet but all have a slight back and forth play in them. Looking close at the belt on idler pulleys when engine is at idle the belt has slight back and forth movement.

 

From what i understand from previous comments on this forum, those idler pulleys are supposed to have some play/wobble in them, working as intended.

 

I’ve never seen a belt rust. I have seen pulley and idler pulley rust.

 

UPDATE: I did take it to the dealer and they said this is fairly common. Some vehicles/belts do this, others do not according to them. It does not affect the performance or longevity of the belt and they would not replace it.

There are no fluid leaks anywhere, unusual noises (other than rattles from the dash and door panels), and the truck is used every day of the week. The truck does not go off road other than an occasional gravel road and is well maintained.

I am not sure I believe them but I do not have the time or patience to press the issue with them any further or to get Toyota Corporate involved. I do not have another dealer within 150 miles so going to another dealer is not an option.

The condition of the belt looks good otherwise, and the pulleys seem fine with no unusual play or noise. I have purchased another belt and plan to replace it.

 

X2...

 

although it appears to be a clamp mark, that is not a clamp mark on the hose. the clamp has never been loosened and moved. it is a water mark on the hose from when i washed the truck.