Belt tensioner for my Toyota Yaris

Jacob Allred

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

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.