Yesterday while my husband was parking the Blazer he said he heard a slight 'rattling or scraping' noise and then when he came to a stop, the engine stalled. He restarted it, the same noise occurred but louder, and it stalled again. Upon opening the hood, he found the serpentine belt had come completely off in one piece.

He called AutoZone and the guy who answered said to check the condition of the belt but that in his opinion that it's the tensioner pulley ($40) that's bad. My husband (bless his heart!) assumes because the belt is in one piece that it's good! It's shy of 3/16" thick and has horizontal cracks about every 1/4" across the six 'tracks'. Somehow, I have to disagree!!!

My question is: How do you know if it's just the belt or if the pulley has to be replaced too? If this means anything, he said he can hand-turn the bolt on the 'top' pulley (which we can only assume is the tensioner one since the diagram doesn't have names).

Thanks; any input anyone can give will be greatly appreciated.

Patti

 

There's two pulleys you can check. Idler, upper center is a metal smooth one. On the passenger side below the alternator is the spring loaded tensioner with a plastic grooved pulley. Both should turn smoothly and if you try to wiggle them side to side, they shouldn't. The bearings can go bad in the center (you replace the pulley). If you have to replace the tensioner one take the bolt out that holds it to the engine. It's easier to do if you get it out in front of you. I replaced my tensioner a few months ago, the morning squeak was annoying me.

 

Thanks, RonJon -

Well, apparently what we are calling the tensioner is what you are saying is the idler, and this is what has the loose bolt and it does wiggle. He took a picture of the diagram, and judging from the way it showed the belt going under it, my logic sensed it had to do with tension. So much for logic! Do you think this idler pulley has anything to do with WHY the belt came off, or is it just the RESULT of it coming off? And/or, do you think the tension pulley needs to be replaced?

BTW, this is a '96 S-10 teal Blazer ready to hit 200K miles and you can imagine how much has gone into life support over the past few years -- but she's so pretty!

Thanks again,
Patti

 

neither one of those pullies should move-other than rotation.

i'm really curious as to why that bolt loosened off, i've never seen that hapen before, and i've routinely spun my 4.3 up to 7 grand (in my Jimmy). that doesn't mean it can't happen, but there has to be a cause.

try just the bolt in the hole-is it sloppy? if it is, then it sounds like the bracket might be damaged (the threads for that pully bolt). if it isn't, just clean the bolt & hole, and put some blue Loc-tite on the threads-not red, you'll never get it apart later (kinda a problem if the pully does need repalcing).

keep us posted on what happens.

 

We had a friend of my son take a look at it earlier and the idler pulley's bearings were all ground up. I didn't read your message beforehand, so I don't know if he checked to see if the threads were ok or not. He's picking up a new pulley tonight and putting it in tomorrow morning. He couldn't get a new belt because the place he went to won't get more in until Tuesday, but he said the old belt isn't too bad for now.

I know I'm out of my realm of expertise here, but let me ask anyway: Since there was no damage to the belt, is it possible the pulley bearings went, causing it to seize and thereby stripped the bolt? Also, I would think the belt fell off as a result of this and wouldn't cause the damage to the pulley.

Thanks for your input. I'll keep you posted.

Patti

 

When the bearings went the idler pulley started wobbling which probably threw the belt. Make sure to check the tensioner as well as long as the belt is off. As for the belt, IMO i'd change it just to be safe. Keep the old one as a spare, preferrably in the truck, 'cause if it fails you won't get too far.

 

In the last 3 yrs I have had that darn idler pulley go out on me twice, Its not a bad idea as routine maint. when you have have the hood up and the engine running to take a look at all your pulley's. If the idler pulley is doing a dance (boucing up and down) its time for a change or you hear a rattling noise coming from it.

They are a easy enough fix once you done it once..I also buy the goodyear belts with a life time warranty, you pay a few more bucks, but if it ever goes bad, take it back a get a new one. There is no warranty on the idler pulley however. Shucks on that one, they are know to go out from time to time...

 

Hi all! I just replaced my belt tensioner, serpentine belt, and alternator(was binding). I was still getting a screeching clicking first thing when cranked everyday. The screeching would go away but the clicking continued. Took it to a mechanic and had the tensioner replaced again. It is still making a loud clicking when accelerating that will sometimes go away, sometimes not. The mechanic (very trusted and good) said that he couldn't find anything wrong and the noise was just an annoyance. I have a 2001 Chevy Blazer LT 4WD.
Any ideas? He didn't seem to think it was the idler pulley. Feel free to respond here or email at winterhawkhs@yahoo.com