Bad alternator belt, or bad alternator?

[xfeejayx]

Hey guys. Thanks for the look.

My charging light came on, and I know that the belt has been going bad. I finally pulled it and here's what I can see:
The belt is an original Toyota/goodyear. That means that its a high quality belt, but that also means that it is the original and has 142K miles on it.
There are a lot of obvious cracks on the rib side, lots of smaller cracks spanning the width of the smooth side.

About the belt being old/bad/loose, can it loose enough tension just by stretching/cracking so that the alternator no longer charges?

I'm going to get the alternator tested at autozone, but if its good, I'd like to know if the belt can be the problem. Unfortunately, I didn't have enough on my battery left to check if the AC would come on (after i was dumb enough to drive it a couple times without it charging).

Also, when installing a new belt, should I tension before or after the 5 minute break in? I just read in another thread that deflection in a belt should be set to (distance between pulleys)/64. That sound about right to you guys?

Thanks for the help!

[Mike Gerber]

If you don't hear the belt slipping, especially when the engine is cold and first started, the problem lies with your alternator. You will probably need to change out the alternator but having it tested is still a good idea, if even just for peace of mind so you know that you are not spending the money on something you don't need. Change out that cracked belt while you are changing the alternator. A good rule of thumb on belt tension is a half inch of deflection at the center of the belt's longest span accross the pulleys.

Mike

[KimMG]

Adjust the belt to its proper tension when installing and check it later to make sure it still has the proper tension.

[RIP]

From your belt description you need a new belt whether you change or test the alternator or not. Makes more sense to just change the belt, tension it correctly and see if your problem dissappears. Or just leave the old belt installed, adjust the tension tighter and see if the light stays out. If it stays out, your alternator is good but, you still need to change the belt.

To check the alternator (once it's running) using a meter check for at least 14vdc across the battery terminals. This indicates the alternator is supplying enough voltage to charge the battery.

[xfeejayx]

thanks for the replies guys. it was the alternator. Guy put it on the tester, hit the button, instant fail. Eh, 142k is plenty from an alternator, don't ya think?

I may have said this before, but I love how serviceable this car is (98 2.2L). Alternator and swapped in about 30-40 minutes of work. GO YOTA!

[2000izusu]

what kinda alternator did you get? new, rebuilt?

thats odd but not unheard of for a denso alt to fail before 142,000. usually they go past 200,000. mike

[xfeejayx]

reman (read rebuilt) from autozone.
lifetime warranty is plenty good for me.