Serpentine Belt

For what it's worth, I'm not a fan of replacing things based on age alone (myself included), but I'm not a mechanic or a dealer, so I don't have a vested interest in recommending that something be replaced when it's not necessary.

I'd look for any of these things before I'd go ahead and replace it:

• Squealing sound: Belt slipping
• Chirping sound: Misalignment of an accessory drive pulley
• Frayed belt edge: Misalignment of an accessory drive pulley
• Polished belt edges: Belt slipping
• Glazed belt grooves: Belt slipping
• Fluid contamination: Oil, power steering, or coolant leak
• Excessive cracking: Other than severe old age, defective tensioner
• Whirring sound: defective bearing in tensioner pulley or idler pulley
• Rhythmic noises occurring at engine speed: Delaminating belt backing, chunking of belt ridges, or foreign object embedded in belt groove
• Grinding sound: damaged bearings in driven accessory
• Belt coming off: Pulley misalignment, belt misalignment on pulley, defective tensioner, or bearing wear in tensioner, idler or driven accessories

 

I think the recommended schedule is 120k miles, but you can inspect it and see if it looks healthy. Most people who have changed them notice lots of small cracks in the rubber when you look closely, but the cords and overall integrity are usually still good at 120k miles.

I changed mine at about 125k miles (200,000 km) and wrote a bit of a guide here: V-belt and plugs, 200,000 km maintenance. (pictures) | PriusChat

The main problem that people seem to have with this job is loosening the pulley wheel bolt. So do make sure you've got the right tool for the job and don't round it off. The rest of the job is pretty easy.

 

I do preventive replacement of the ICE water pump every 150k miles (concurrent with the coolant refresh) and replace the serpentine belt at that time as there is no additional labor cost and the belt part cost is minimal. Only done once so far as my 2004 Prius is only at 265k miles.

JeffD

 

Yes bolt B is the one that locks adjustment and makes tensioning pulley straight. Bolt C adjusts the tension (if B is lose) but tension will get bit tighter when you tighten bolt B.

 

I did mine at 130K when I purchased the car. Kind of a no brainer to me for a 8 dollar part at that mileage. Here's a good link:

Belt change how-to with photos | PriusChat

I also found some stuff on youtube that might help you. It was 30 minutes max and I'm no mechanic.

 

I suggest you inspect the engine coolant pump to make sure the bearing is not seeping coolant. If it is, the pump should be replaced when you replace the serpentine belt. My post below explains how to do that.
How to replace engine coolant pump and thermostat | PriusChat

Use a quality 14 mm, six-point socket on the idler pulley nut. Use an extension on the cheater bar as needed for leverage.

You are correct that the Prius does not have an auto tensioner pulley, you need to adjust the tension manually when you install the new belt. The tension on a new serpentine belt is adjusted so that 22 lbs of force applied to the longest run of the belt results in 0.4" deflection.

The cracks are going to be on the inner surface of the serpentine belt so you need to remove the belt to see them.

When you look at the outer surface of the belt, you will probably notice that the rubber is getting shiny/glazed. Compare the appearance to a new belt. That results from the belt's outside surface slipping on the coolant pump pulley.

An excellent idea to replace the belt in the spring when ambient air temps are pleasant.

 

Thanks for the great thread. My 2005 has 77k on it now. The belt looks good, no weeping at the bearing, so no belt worries it seems.

- Galaxy S5

 

81000 on the '05 G2 now, serpentine belt still looks good. No reason to change it yet I guess.

 

My wife's 2008 has 137k miles on it with the original belt. I started getting nervous about the belt breaking and leaving her stranded. After reading the great instructions in this post, I decided to tackle the job myself. I bought the new belt at the Toyota dealer in Bimingham, AL for $20. After getting my tools together, it took me between 15 and 20 minutes to get it done. Fortunately, I have a slender arm to get between the pulley and the frame so I did not have to crawl under the car. One of the easiest jobs ever! Thanks for all the good posts that gave good information. The old belt did have cracks in it, but it would have lasted longer. But for $20, I do not have to worry about it. The Prius has got to be one of the best cars ever!!

 

At 137k miles, I would've tackled the water pump at the same time

 

Thinking about mine also at almost 90K. Wife's car don't need to leave her stranded. I bought an OEM belt on eBay for $8. Took about 2 months of casual perusing to find one.
Part number: 90916-02570

If u have the time best to buy it online much cheaper.

I like the auto tensioner on my Crown Vic. One of the few things Ford did right. On this car best to install it just snug and put the car in Inspection Mode and let it idle for about 15 mins and then go back & tighten it to spec. It will have broken in a little.