Squealing serp belt

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Herb Kauhry - 16 Oct 2004 16:04 GMT

'97 Explorer Limited, V6 SOHC:

I've been trying to silence my serp belt since I replaced it a few months
back. I noticed that the smooth idler pulley (above the fan and to the
right of the alternator) seems to have originally been coated with something
grey (and perhaps, "non-slip"). Mine is quite worn and even shiny in spots
with bare metal showing through (perhaps 50% of the surface). I've tried
washing the belt and pulley to degrease them. Better now, but only
slightly.

With the pulley surface so obviously worn, it indicates the belt has been
sliding over it. But I don't know how long it's been that way. The
original belt never made a sound, just got cracks in it, which is why I
changed it. Maybe the pulley has been ths way for a long time and isn't a
problem.

Anyone know if the pulley actually has/had an anti-slip coating of some
kind? I may try to buy a replacement, but rather than a shot in the dark, I
thought I'd ask for a second opinion here.

thanks,

HK

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Herb Kauhry - 16 Oct 2004 16:34 GMT

Freaky... Went to Google for more info and found myself (and this post) on
www.talkaboutautos.com Hmm, they mirror the usenet group, and with a nice
search function that doesn't feed in all the annoying commercial hits that
google gives us.

> '97 Explorer Limited, V6 SOHC:
>
[quoted text clipped - 19 lines]
>
> HK

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Herb Kauhry - 20 Oct 2004 04:02 GMT

Well, after getting a replacement tensioner and idler - and replacing them -
the squeal is still there. However, I have determined that it's the
alternator dragging. When I remove the "+" lead that goes over to the
battery, the squeal goes away.

The battery is a year old, and I see no symptom of a low
battery/non-charging condition. So maybe the alternator is bad? This seems
like an odd thing to happen. The alternator turns smoothly, so no bearing
trouble there.

> Freaky... Went to Google for more info and found myself (and this post) on
> www.talkaboutautos.com Hmm, they mirror the usenet group, and with a nice
[quoted text clipped - 27 lines]
> >
> > HK

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Fred W. - 25 Oct 2004 22:14 GMT

> Well, after getting a replacement tensioner and idler - and replacing
> them -
> the squeal is still there. However, I have determined that it's the
> alternator dragging. When I remove the "+" lead that goes over to the
> battery, the squeal goes away.

Just as a point of reference, this is not a good thing to do. You could fry
a lot of expensive electronic components by disconnecting a reconnecting the
battery when the engine is running.

> The battery is a year old, and I see no symptom of a low
> battery/non-charging condition. So maybe the alternator is bad? This
> seems
> like an odd thing to happen. The alternator turns smoothly, so no bearing
> trouble there.

The alternator is not likely to be bad unless it cannot output the power to
recharge the battery. You can bring it to just about any parts store and
they will bench test it for you. Of course, since they sell alternators,
there is a chance they will tell you it is bad no matter what.

My guess would be the battery it not charged and is drawing too much load
from the alternator. When you disconnected the battery you disconnected the
load. The alternator was still spinning and you were not getting the
squeeling. That tell me the likely problem is the load not the source.

-Fred W

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Herb Kauhry - 26 Oct 2004 00:29 GMT

I didn't say I did this with the engine running - it wasn't. I was
disconnecting the lead from the alternator which GOES to the battery, not
the battery.

What I have to figure out is, is there an excessive load on the alternator
from somewhere (like the starter having drained the battery and suddenly the
alternator is putting out a lot of current to recharge it) or is the 12v
from the battery doing an "EMF brake" thing on the alternator
for some reason (I wonder if this can happen when a diode in the alternator
opens, or the regulator has a problem?) Since the alternator seems to be
charging, I'm puzzled.

Signature

> > Well, after getting a replacement tensioner and idler - and replacing
> > them -
[quoted text clipped - 23 lines]
>
> -Fred W

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