Belt Squealing after lights dim

I have a 97 Chevy Lumina. For some reason, when driving down the road,
for no apparent reason, my lights will dim and the heater slows down.
A 5-10 seconds after that happens, my belt starts squealing loudly.
Sometimes turning off the heater stops it. Sometimes, I have to let
off the gas to stop the squealing. Any ideas? I've had the belt
professionally lubricated and that didn't help at all. Could the belt
just need replaced, or could it be something more?

Thanks...

>I have a 97 Chevy Lumina. For some reason, when driving down the road,
>for no apparent reason, my lights will dim and the heater slows down.

Probably when the electric fan kicks on. They tend to draw their fair share of
amps.

>A 5-10 seconds after that happens, my belt starts squealing loudly.

Is this a serpentine belt? I would be inclined to believe either the tensioner
is not tensioning, or the alternator's bearings may be seizing up.

>Sometimes turning off the heater stops it.

Thus reducing the amp draw.

> Sometimes, I have to let
>off the gas to stop the squealing.

Me too, but sometimes I leave the wife at home.

>Any ideas?

Yepper. Check that ol' belt tensioner, and the alternator pulley.

>I've had the belt professionally lubricated

Huh? I'm pretty sure those things are meant to run without lube.

>Could the belt
>just need replaced, or could it be something more?

The belt may need to be replaced. Hold it up to the screen so I can see it more
clearly. I'd go with a new one if it has streched to the point where the
tensioner cannot accomodate it's increased diameter, but that would take quite
a bit of stretching.

My advice is free, along with the smart-ass humor.




I marched for peace, right along with the rest of the Division.

belts chirp, bearings squeal

I don't know enough about alternators to say if a drop or two of oil on
the shaft might quiet it down for a while. If it does and it starts to
squeal again after a while then it was definitely the bearings. That means
a new or used alternator or a rebuild. For my car used was cheapest.

) writes:
> I have a 97 Chevy Lumina. For some reason, when driving down the road,
> for no apparent reason, my lights will dim and the heater slows down.
> A 5-10 seconds after that happens, my belt starts squealing loudly.
> Sometimes turning off the heater stops it. Sometimes, I have to let
> off the gas to stop the squealing. Any ideas? I've had the belt
> professionally lubricated and that didn't help at all. Could the belt
> just need replaced, or could it be something more?
>
> Thanks...
>


--
------------------------------------------------------------------------------
William R Watt National Capital FreeNet Ottawa's free community network
homepage: www.ncf.ca/~ag384/top.htm
warning: non-FreeNet email must have "notspam" in subject or it's returned

Yes, it is a serpentine belt... Here's a picture I found on Google
that looks a lot like it, grooves and all.

http://www.shokan.com/catalog/images/Serp%20Belts2.JPG

I took my car in last week to the mechanic and they lubricated it for
me to stop the squealing. They said that sometimes that helps. I know
they may a type of spray for belts as well, so I assume it's a similar
concept. On the good note, they didn't charge me a dime, so that's a
plus.

The car's got about 80,000 miles and the belt looks a little worn, but
not bad. I just want to have an opinion before I take it back in so
I'm not overcharged or ripped off.

Thanks...

Does the garage that 'lubed' the belt also supply the local tow truck?
You are either describing a shined up belt that won't grab any more or a
bearing about to seize up. My money is on the belt.

I polish up belts all the time and get the same symptoms. A squeal
later and it charges some again, but it won't fully charge my battery
and if I ignore it, I 'will' end up with a dead battery pretty fast.

I kill mine by taking my Jeeps out in the mud holes and dirty trails.
The mud is liquid sand paper and I have gone through as many as 3 belts
a year some times.

I test the belt by having a cold off engine and trying to hand turn the
alternator pulley. If I can hand turn it, it will not grab under load
and it will slip. Alternators take a few HP to spin up under load. If
you can hand slip it, it needs replacing or it is loose. If it has been
loose long enough to polish up or need a 'lube' job, it needs replacing
anyway.

Mike
86/00 CJ7 Laredo, 33x9.5 BFG Muds, 'glass nose to tail in '00
88 Cherokee 235 BFG AT's

wrote:
>
> I have a 97 Chevy Lumina. For some reason, when driving down the road,
> for no apparent reason, my lights will dim and the heater slows down.
> A 5-10 seconds after that happens, my belt starts squealing loudly.
> Sometimes turning off the heater stops it. Sometimes, I have to let
> off the gas to stop the squealing. Any ideas? I've had the belt
> professionally lubricated and that didn't help at all. Could the belt
> just need replaced, or could it be something more?
>
> Thanks...

On 10 Dec 2004 18:57:58 -0800, wrote:

>I have a 97 Chevy Lumina. For some reason, when driving down the road,
>for no apparent reason, my lights will dim and the heater slows down.
>A 5-10 seconds after that happens, my belt starts squealing loudly.
>Sometimes turning off the heater stops it. Sometimes, I have to let
>off the gas to stop the squealing. Any ideas? I've had the belt
>professionally lubricated and that didn't help at all. Could the belt
>just need replaced, or could it be something more?

Almost positive it's your belt. I have a voltmeter installed, and the
heavy squealing only happens when the voltage is between 13.5 and 14.0
volts on start-up (14.25 is about normal for the warmed-up engine).

The squealing comes back if I put too much electrical load on it.
Examples are headlights and especially the heater fan. Putting the
heater fan on 'high' can decrease overall voltage by as much as 3/4
volt.

My car did this for about 6 years before I finally did something. I
replaced the belt and "roughened up" the alternator pulley grooves
with a wire brush. This stopped it for several weeks, but it still
comes back occasionally in cold weather. From what I've heard on
other car groups, OEM belts come with a sticky substance on the
grooves...aftermarkets dont usually have it.

Good luck,
Dan

Thanks to all for your replies.

I took in the car to the mechanic and their diagnosis was the water
pump. I had noticed prior to taking it in that the coolant level had
dropped somewhat. Apparently it was leaking and getting on the
serpentine belt. This led to the belt slipping. They replaced the
pump and all is well again.