Belt tensioner for my Toyota Yaris

I have a 2007 Toyota Yaris sedan. I love it. The thing is ridiculously reliable, nearly maintenance free, and gets great mileage. The one thing that drives me crazy is the serpentine belt. The dumb thing is next to impossible to set to the proper tension because Toyota decided not to include any sort of belt tensioning hardware. Instead, they expect you to take a crowbar to your alternator, stretch the belt to the proper tension, then somehow hold that position while tightening two bolts. Yeah. Right. I can totally do that all by myself.

I did some searching and found a post at Yaris World that gives instructions for modifying a Scion xD tensioner to work in a Yaris. I also found a post that uses angle iron, but I decided to go with the purpose-built OEM parts. The basic idea is to buy a few Toyota parts (16385-37010, 90105-08433, and 16381-37010 from a Toyota dealer or online from somewhere like Toyota Parts Zone) and then saw off a few bits of 16381-37010 so it will fit in a Yaris. The OEM part has a bolt on the wrong side (saw it off) and a lip that gets in the way (saw it off, too). This took me a few hours because I didn’t have the appropriate tools. Probably could have been done in just a few minutes if I had an angle grinder. Once the part is modified, it is easy to replace the Yaris bracket with the new one, tighten it up, and BAM! Belt tensioner for the Yaris. No more squealing belt. No more trying in vain to get the belt tight enough using whatever lever I can find. Just quick and easy belt tensioning.

See below for the before and after shots in my Yaris:

Original hardware

Original hardware

New hardware

New hardware

If you notice, the original nut and both original bolts are being used. The only original part that I removed was the sliding bracket. This means that, once I use the long bolt to get the belt to the appropriate tension, I can retighten all the original bolts and nut so they hold everything in place instead of the long bolt and little tensioner bracket. In other words, the new parts are as safe and reliable as, if not more safe and reliable than, the original parts.


  1. thank you for this excellent fix. my husband how has his sanity back!

  2. Perfect!!!!! How much will it cost me for you to make me one. You can ship it and I will take care of the rest. My kids nor wife even want to ride in my 2012 yaris.

    My belt was replaced 2 months ago, but belt still sounds worse than….well I bet you know how bad they sound. Everybody looks at you as if you don’t take care of your car.

    • Sorry, I don’t really have the time to do it. I bet if you used an angle grinder (super cheap at Harbor Freight) you could make the part in just a few minutes though.

      Or you could try using a belt tension tester to help you know if you have your belt tight enough. On my Yaris I had to tighten the belt a lot more than I thought I should to get to the right tension.

  3. Hey,

    So I made this part and it worked out very well, after getting a mechanic to cut off my 14mm bolt under the alternator as the previous owner had stripped the bolt so much using the wrong size wrench.

    Anyways its maybe 7 months since the install, I was adjusting my new LED headlights and the bracket had cracked in half closer to the motor mount of the bracket….

    Have you had this happen or is it still working fine?

  4. Thanks. Ordered the same parts and completed the modifications last night on my 2009 Yaris. Works beautifully.

  5. This modification has been a life saver for my son’s car. I ordered the parts from a local Toyota dealer and picked the parts up. It cost me $17.70 for the parts and a bit of time cutting the sliding bracket with a hack saw. The first time I adjusted the tension until the squeaking when away. I waited a week to tighten because of belt stretching. I had to adjust a final time because of the additional load created by the AC. No more squeaking and embarrassing noise.

  6. Did you know the Yaris has a little glitch in the computer that causes the alternator to produce full load when you first turn the key? This in turn cause the belt to squeal on startup almost every time. Something to try the next time you start the car is to just turn the key to on and wait a few seconds before turning it to start. Usually this stops the squeal.(on start up) I am guessing it has to be that the computer needs a second or two to make everything right with the start sequence and not demand the alternator to charge.(?)

  7. Just put hacked one together using my angle grinder. No more belt squealing. Thank you for posting!

  8. Hi… I am having this squeaking issue with my 2010 yaris. We changed the serpentine belt and of course that didn’t help. I am not mechanically inclined… do regular shops do this sort of thing? I don’t know what to do and the squeaking is out of control!!! thanks.

    • This is a fairly easy issue to fix, but takes a fair amount of brute force. The Yaris wants the belt to be VERY tight. If you are still getting squeaking, then you likely just need to make the belt tighter.

      A regular shop could help you with this. I’m not sure what they’d charge.

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