Hey guys, I've read in other posts (mostly 4th gen) about the idler bearings. Has anyone replaced these? Rock Auto calls out Idler Pulleys, I assume these are what they mean when talking about replacing the bearings? Also, Rock Auto calls out an upper and lower any input? Thanks!

See the diagram. Several idler pulleys. The other accessories also have bearings. When you take off the belt you can spin the pulleys with your hands to see if they turn smoothly. Replace if they’re bad. They’re expensive, I wouldn’t replace unless necessary. They will usually give you some warning but I just had a friend who had one go out while up the mountain and he drove 20 miles on a frozen one. He said it cooked the belt and made a hell of a noise but made it without breaking.

A couple of notes, since I just did mine:
- I have a 2010, and I'm fairly confident the OEM (unmarked) belt was a 2145, based on length, so that's what I used. It sounds like they may have switched at some point.
- The hole in the tensioner was much lower than I was expecting - even though the pictures do show this, I thought it was part of the tensioner pulley when in fact it's part of the assembly below the pulley.
- I had to use a 1/2-in ratchet (with an extension, but then a short socket) to get enough leverage to move the hole into the next "section" that it grabs on. The ratchet has to go between a hose and the fan, so getting the right length tool is important.
- This may be a "duh" thing but at first inspection of the diagram I thought the belt would end up pulling out on one side or the other of the water pump/fan shaft, but that's not the case. You have to feed the belt around the front side of the fan to get it out.
- At first I didn't think the 2145 was going to fit, but the belt wasn't properly seated in the crankshaft pulley. I put it back onto the tensioner last, which was nice because even loosened it was snug, giving me some guarantee that I had threaded it properly.

Good notes. I've got 9,000 miles and 8 months on my replacement (2150). Still looks good. I will have to take a pic of the tensioner to see if it has slacked at all.

Guys, Great information. I've been wondering what I'd do "100 miles from nowhere" in the desert if my belt breaks on my 2014 4Runner. One thing in the threads that bothered me, and that was find the cheapest belt. The belt is one of the "single point failure points" on any vehicle. If the belt breaks you're not moving far. Another single point failure point is the battery (I installed dual batteries). I also carry 2 spare tires. I know people who have had 2 flat tires off-roading. Why would anyone want the cheapest belt (which usually means low quality)! I want the highest quality belt, which probably means more expensive to manufacture. I was speaking with a Jeep owner yesterday. He said he installed an "upgraded" belt on his Jeep. The upgrade was a Kevlar infused/coated belt. Much higher quality and reliability than the OEM Jeep belt. Anyone heard of such a belt? I'm starting my research now.

Literally the best belt out there has always been the Goodyear Gatorback. It's distinctive because it has cross-cuts in the ribs, looking almost like alligator skin. That division of GY was bought by Continental and it's now marketed under the Continental Elite brand. Careful though when buying, there is a Conti belt without the cross hatching too. I got that one by mistake the last time I did the belt on the wifes car (QX56) which is a notorious belt eater. Worked OK so far but we will see how long it lasts before she gets the cold startup squeak.

Bando is the OEM. If there was a quality issue we would've probably heard about it by now. Your tensioner and idler bearings are more likely to go out before the belt breaks. Hope you've got spares for all of those.

Thanks for all the info shared on this thread. Just wanted to share my experience.

2013 Trail at 92K - OEM belt was 2150. Amazon says 2145 for my truck but I purchased the 2150. The original was showing its age but looked to have some life left in it. Bando replacement from Amazon looks to be quality.

Overall easy job. Couldn't find the hole to lock it back but an 18" breaker bar with 12 point 14mm deep socket made the job easy. Hardest part in reinstallation was getting it under the fan pulley cause the clearance was so close.

I was going to replace tensioner and/or pulleys but they're stupid expensive and luckily they all look/sound good

So at what mileage point would you consider replacing the serpentine belt? I'm getting ready to turn 30K but also gonna be taking a 13 hour road trip to Florida in May.

Somewhere between 80k and 100k, personally. My truck's a 2010, so it was getting up there in total age as well. Didn't see any defects on the old one when I took it out, though.

Good info here So tagged .

I bought the 2150 Bando Rib Ace off Amazon. Part number matches what's recommended on Bando website and was ~1500 reviews. My concern is that the ribs are some kind of felt while the front side is I"m assuming the EDPM rubber printed on it.
Should the ribs be felt or is this some kind of knock off? Felt doesn't seem like the right material for a belt.

I definitely understand your concerns, but honestly I hadn't thought that far into it. I have faith that the engineers at Bando balanced the quality/durability and materials/price..... They seem to have their hands in a whole lot of the auto industry and if they sucked they would lose their contracts. Slap it on the truck and feel good about it being replaced!

So no one has tackled the belt tensioner yet it seems? Mine is a 2012 Limited with 146K miles ... so I'm going to do it all as preventative maintenance. I bought all 3 idler bearings, as well as the tensioner (ouch, expensive)
Looks like the alternator as well as the AC compressor has to come off to get at the tensioner .... I can't find a write up or You Tube video on it ... but I'm going to tackle it.

The only time I've ever had a problem with a tensioner is when the tensioner can't move. I had a vehicle that the belt lasted quite some time and when I replaced the belt, the tensioner was "stuck". New belt squealed. Took belt off, lubed up the tensioner, made sure it stroked properly and went on with life.