I just went thru this.
Gates belt change and idler pulley.
Has less than 3000mi on it and squeak-squeak-squeak. It was embarrassing sitting at a stop light.
So I buy and install the tensioner pulley. Still squeaked.
I spray a little laq. thinner on the belt. It quieted right up for about 30sec.
I spray it again. Same thing but now I can tell there is a noise coming from the alt.
Pull the alt and had the bearings changed in it. The back one was not great.
Reinstall the alt. Squeak-squeak-squeak.
Go down and get another new Gates belt. I get home and he gave me the wrong one.
I had the 3000mi belt off already.
Back to the store with both belts. Get my money back on the wrong one and they warranty the 3000mi one.
Install the new belt. No more squeak.
Spent about $130 total.
Gates is all I will run and have been for 20+ years. This is the 1st belt I've ever had to warranty. It's $32 thru O'Rilieys.
Gates does not make a Green Stripe belt for this application. If they did that is what I'd buy.