my van has been squeeling for a while. this mostly happens at low rmp (at idle, but also when off the gas entering an intersection). Really loud. Really annoying. This seems to be more pronounced in cold weather.
Then one day, I started it up to warm up and let it run in the yard for a half hour. It was dusk and the auto headlights were on. After a half-hour or so, there was a new warning light blinking and an alarm going off. I shut the car down and when I tried to restart it, the battery was dead. I got a jump start, and drove off and the battery charged fine.
So I'm thinking that the alternator is gone. Brought it to the shop and they tested the alternator and said it was fine. They threw a new belt on. I'm then thinking that the alternator must be failing at low rpm and they don't test for that.
After reading this formum, I decide to check the bearings on the alternator. But also while reading, I see that the belt has to be pretty tight and there is a common issue among Toyotas and maybe these vans. I follow the instructions in this thread (thanks especially for the diagram). Loosen up the alternator, get the belt off and spin the pulley on the alternator. I'm no expert but it feels fine. A little resistance as expected but spinning by hand.
So I tighten it back up and I realize when I get the tensioner bolt back to where it was that it has not been adjusted in forever. The rust on the bolt makes it difficult to get past where it had been for, well forever. So I get it cranked in about six more quarter turns, checking the tension of the belt in between. The adjustment is very fine, so it took a lot of adjustment to get the belt as tight as it should be (tight enough not to slip by hand at least).
Fired it back up and problem solved! Lesson learned. Just tighten the belt first.
A couple of notes: folks in this forum keep mentioning a serpentine belt. There are two v-groove belts on the van. One goes toward the front and hits the AC and the alternator. The other one goes toward the back and hits the power steering. Traditionally, a serpentine belt covers everything. This is not the case here. Two belts. The second belt must be accessed through the front-right wheel well by removing a plastic shroud. I didn't check the PS belt, but I am going to now. I think you also have to take the wheel off.
The other note is that the shop changed my belt without loosining the tension adjuster under the alternator. Again, I'm no expert, but I don't understand how they did this. I know this to be the case becuase the bolts were frozen. Breaking them free took some work and some lubricant, as described in this forum.
So the new belt was still too loose. How did they do it? I don't know. I'm guessing they cut the old one off and then used a screwdriver to jump the new belt onto the pulley. I really don't know. But the new belt running loose, would certainly get glazed in no time since the squeeling persisted.
I had to create a login on this forum to see the pics. It was worth it becasue it made the job way easier. Since I am a member now, I figured I would add my two cents and hopefully make it easier for someone else in the same boat. Tighten the belts first.
2004 Sienna XLE Limited AWD, 140k miles