Belt system or something is screwed up...

Odin8 · #1 (**permalink**) 03-07-07, 07:05 PM

Well. This sucks. I just replaced the accessory belt and the belt tensioner, and now something is screwed up.

I put it all back together, started it, and it is making this nasty "whurring" noise...kinda like if someone with off road tires drives by you doing 100...that kind of noise. Then I figure out, if I start revving it a little, my alternator will stop charging at around 2500 RPM, so it seems the belt starts slipping at around 2500? Idle, it is fine...I can slowly increase and hold it anywhere up to right around 2400, and it'll be fine...soon as I pass that, my voltage drops like a rock and Battery No Charge comes on.

I took the new tensioner back off, put the old one back on, same thing. Put the new tensioner back on. I've taken the belt off, checked the routing and how it was seated about a 1/2 dozen times. Visually, the belt looks still new, inside and out, no marks or anything. Poked all around the area too, nothing seems to be touching/rubbing the belt.

I dunno WTF to do. I hand spun everything too, except the AC clutch that I couldn't reach well, so I know nothing is siezed. Before I touched the belt and tensioner it was absolutely fine. Any ideas? Anyone? I hate how this was gonna be a quick afternoon thing to do and now I'm porked, just because I didn't want to listen to my tensioner pulley chatter.

deville555 · #2 (**permalink**) 03-07-07, 07:14 PM

Have you checked your power steering fluid?

Odin8 · #3 (**permalink**) 03-07-07, 07:20 PM

Somewhat recently...it was decent. What does that have to do with this? Low fluid level would make the pump harder to turn or something?

Odin8 · #4 (**permalink**) 03-07-07, 10:42 PM

The belt only goes on one way, correct? The ribs are all even on the belt right? I have no idea what the hell I did, this is bugging me wicked bad, and I don't want to pay someone to fix it now either. Could I have bent a pulley somehow taking the belt out? I'm going to have to bring it to my mechanic tomorrow morning if I can't get this fixed, I have work tomorrow.

That sums things up pretty well.

donwon · #5 (**permalink**) 03-08-07, 09:17 AM

There should be a digram of the belt routing somewhere under the hood.
If the belt is routed right you may have another problem that is just a coincidence.
I don't know what the alternator will do if it turns backward besides not cool itself.

Odin8 · #6 (**permalink**) 03-08-07, 12:51 PM

Is there any possible way of routing the belt around every pulley that would result in the alternator spinning backwards? I was looking at this, and I couldn't really come up with any theoretical way of making the alternator spin backwards, never mind if the belt itself would physically fit. I'm being told that I could have spun my alternator backwards and broken brushes or something?

97STS4ME · #7 (**permalink**) 03-08-07, 10:03 PM

The alternator should spin freely in either direction with no immediate consequence. And as far as I can see, no I dont see a way to make it spin backwards unless you dont have it routed around every pulley.

Did you watch the belt any while it was doing this? Does it rub on anything? Did you leave a wrench on the tensioner? Or somewhere else under the hood?
Did you get the belt routed properly behind the tensioner? Is the belt routed exactly the way it is pictured in the routing diagram under the hood?

Odin8 · #8 (**permalink**) 03-08-07, 10:52 PM

Yah, first thing I did when I started it was sit there and watch it for like 10 minutes. It isn't rubbing on anything as far as I can tell, and there aren't any marks on the belt that would indicate that it's touching something. Picked all the wrenches and everything up..I'm pretty anal about that, I had a past experience where I had a wrench thrown at me by a belt because I forgot it down in there and my buddy started it.

Like I said, I took it off and put it back on a 1/2 dozen times to make sure it was right, and I've had 4 different people look at it so far and they all think it's right. If that belt isn't routed right, I'll give up my car.

My mechanic seems to think that I spun the alternator backwards and ****ed something up inside of it. He says he's seen it before on other cars. For once, I'm questioning he's judgement on this one. I can't really offer a good explanation for what's happening myself, but I know I couldn't have spun that alternator backwards and ruined it.

WarrenJ · #9 (**permalink**) 03-08-07, 11:14 PM

I can't imagine you got the belt path wrong, but just to ease your conscience . . . .

Odin8 · #10 (**permalink**) 03-08-07, 11:18 PM

Haha yah, that's one of the pictures I've been looking at. I've been looking at that one, the one under the hood, and another one I got off of a website.

**Ranger** · #11 (**permalink**) 03-09-07, 06:03 PM

I wonder if the alternator is not simply failing and it has nothing to do with the belt (if that is possible in this scenerio).

Odin8 · #12 (**permalink**) 03-10-07, 12:01 AM

Well, the alternator was a brand new one from Cadillac, and it can't be more then 3 months old. So it shouldn't be just failing.

Nothing has been touched yet, and it has gotten better. I won't lose charge until I get almost to redline now, and the noise has gotten a little better. Didn't think alternators were capable of getting better? As far as I'm concerned, this is a problem with one of the pulleys or the belt somewhere, there is no possible way of accidently routing that belt to make the alternator spin in reverse and damage it. Anyone else agree with that?

Mark Bunds · #13 (**permalink**) 03-10-07, 05:56 AM

Spinning the alternator backwards would have no effect whatsoever, and could not possibly damage it. It is simply a three-phase AC generator, and would work just as well if spun in either direction. The old style DC generators, back in the day, might be damaged if spun backwards because they used commutator brushes, but alternators use slip rings which don't care about direction.

ewill3rd · #14 (**permalink**) 03-10-07, 09:48 AM

Perhaps the belt is too long.
I have seen that happen more times than I can count.
If the counterperson gave you a belt that is just a little bit longer than the one you took off, the tensioner will bottom out when you release it and the belt will be loose.
As the engine speed and workload increases on the belt it will slip more.

If you can get the belt off and you still have access to the old belt, you can stick your arms inside and pull the belt tight, you'll know if one is a bit longer than the other.
If you are routing the belt properly this would be my suggestion.
If it is a GM belt sometimes you can still see the old number on the belt and compare them.

Odin8 · #15 (**permalink**) 03-10-07, 11:41 AM

Thanks Mark, that was the kind of info I've been looking for.

Ewill3rd, that was my next thought. Probably tomorrow, I'm going to take the belt off and compare it with the old one that I still have, and then probably swap the old one back on and see what happens.

Thanks for the help so far guys, I appreciate it. I'm sure as hell not going to pay labor on um, what would be my 5th alternator I think.