serpentine belt wear and stretch

Comment in a recent Car and Driver: "modern belts are made of a material that doesn't crack. A special tool checks the belt for stretching. Either it has stretched or it hasn't; there should be no question. Replace it at 100,000 miles..."

Really? I had a belt shred itself about 10 years ago, and with all of the systems that it takes down, I'm used to changing them at 60k. What is this stretch checking tool?

I've got a 2008 Ford 3.0V6 with 60k and saw this and thought it was interesting. Hadn't heard of this change in the belts.

I, for one, would like to see this tool.

I've heard that they wear down before stretching/cracking and there is go/no go gauge that checks the groove depth of the belt. I just change them if they look bad or wont shut up.

I believe this offer is still good from Gates.

http://www.gatesprograms.com/beltwear/beltwear

Lots of new ones are not adjusted, nor tensioned. They are stretched onto the pulleys. Not sure thats the right plan, but it does take away a failure point, I guess.

maybe this explains why belts on sentras/versas always look perfect, yet they are a 30k wear item... hmmmmm
(it doesn't explain why nissan would make you remove most of the inner fender liner to do the belt because it's all one piece instead of a removable flap like their other cars though) /rant
=]

I've got the Gates tool. It's actually kinda hard to use, particularly if the belt is on the car.

I completely disagree about modern belts not cracking, I see it all the time. Especially with cheap Dayco belts. Seems like some of them come off the shelf with cracks built in.

I would agree about the subtlety of these belts with regards to wear and slippage. The degree of wear that changes a belt from working fine into a squealer is all but impossible to discern by just eyeballing it.

I had 60k on my Ranger's first belt before it started squealing (only indication after many inspections). After I pulled it and measured it against the new one I had something on the order of 1/2" of stretch with no cracks, it was impressive, the squealing was not.

A quality belt shouldn't crack under normal conditions. Temperature extremes and heat cycling will eventually cause a failure, though.

I've had good luck with Goodyear belts. I've tried cheap belts only to have them sing and hiss, they were quickly removed and replaced by something good.

Gearheadotaku wrote: I've had good luck with Goodyear belts. I've tried cheap belts only to have them sing and hiss, they were quickly removed and replaced by something good.

when i was trying to figure out which belt to use on my Camaro this spring, i figured it would be cheaper to buy a few cheap belts of various lengths until i found the one that fit and then i was going to return them and buy a good name brand belt... but the cheap belt worked so well that i decided to just buy another cheap one and throw it in the cubby hole in the back of the car... 12,000 miles (and 8 states) later and it still looks and works perfectly and the mark on the tensioner is still lined up with the same mark as the day it was installed in April. there was one intermittent squeak at first that i thought was belt related, but a shot of WD40 into the alternator quieted that right up and it hasn't made a noise since about the first week of May.