garrett376

Is it possible that belts cause the squeaky sound coming from my alternator/fan???

It seems either my belts are squeaky or the bearing is no good on the fan, and am wondering if changing the belts is even worth trying! And what does a failing bearing act like - noise at all RPM? My car has only 48,000 miles - normal for a fan bearing to go?

I have adjusted the tension, since one belt was very loose before. The noise is only present when the engine is cold and running at a very low speed (below 1000RPM). I have removed the belt sensor to trouble shoot, and that's not the source either.

What do you guys think - new belts, new fan bearing? Ideas?

Thank you!

jimq

I am having the very same thing going on. Just ordered 2 new belts. It only does it when cold after sitting a few days. My sensor light comes on and the belt seems fine but a bit loose. Figure if i have to do shims I may as well just change belts. Cant ever get mine to do it when out by the engine. Seems to be only under load.

Doug H

Mine has a very faint high pitched whine/squeek every once and while. Does not sound like belt, but sound like the A/C compressor. My shop surely heard it and didn't say anything about it.

Matt Romanowski

It's always hard to describe noises, but belts are squeeky and can usually be stopped at different rpm. Bearings are a more mechanincal noise and tend to be grindy (but could make a squeel).

Matt

garrett376

I'm going to see if I can record the sound for y'all! I can't describe it either... I'll see if I can get a good recording of it on my little digital camera.... (if my wife finds out she'll ban me from Rennlist...!)

garrett376

Ok, here's what it sounds like. Be careful, since it is an annoying noise!!! You may want to turn down the volume.

I am pretty sure it's the belts, since after a drive on the freeway for about 10 minutes, the sound went away completely. Hmmmm.....


http://homepage.mac.com/guessendo/noisy1.MPG

mojorizing

Hi Garrett,
I watched your video and Siskel and Ebert gave it two thumbs up for the plot.

How about removing each belt at a time and then starting your engine.....first the A/C, then the Alt. and finally the Fan...isolating the problem, and you'll be that closer to ultimately changing all your belts. If the noise is still there. When a belt makes noise, dripping a little water on just that sheave will change or reduce the squelling, that's another method of troubleshooting.

Next time you put up a movie, include some T&A for us viewers.....

C4TT

Mine made noise, and it turned out it was a small heater blower making all the racket back there. We took off each belt to narrow down the noise source. Since the alternator and fan spin at different speeds, they are not connected so one by one you can attain the source of your problem.

Sometime the tension is too light, and it needs some adjustment.. Or a new belt all together...

garrett376

Thanks for the input guys... I will remove one belt at a time - although that means I have to take off the AC belt too.... hmmm, no fun there....


Yesterday I went and got two belts since I think it's just squeaky belts (although I've never had that before!).

It's enough of a nuisance that I think I'll do that tonight - I sound like I'm driving a Ford Pinto or something... It helps that I've got a Cabrio so I can hear it that much better!

Ragin' Bajan

I've had the same sort of squealing for close on two years now, only during winter (which is mild here), and only when the car is cold. After the car warms up, or when the ambiant temperature is high, I've not had any problems. As such, I've put it down to temperature induced contraction in the belts when they're cold.

Jeff Curtis

Chris, nice avatar you have there!

...Hmmmmm, reminds me of some antics some guy in a white C2 pulled at Roebling roads a few weekends ago.

Does the squeel change w/RPM is the key...I thought I had alternator problems shortly after purchasing my 964, but it turned out it was the heater/blower motor in the engine compartment toasting the bearing.

Check it out and let us know.

garrett376

It's no wonder Chris' car has a few squeaks and rattles... based on that avatar I would expect that!

When the engine first starts, for about 40 seconds, there is no noise, then it starts making noise progressively to the point of my little video clip above. It only occurs at idle speed up to 1200 RPM. After that engine speed, I can't hear it at all. My engine is stock, so there's no noisy exhaust or intake to mask noises... (although my Yokohama's are a bit noisy as I've mentioned!).

After about 15 minutes of driving, it's gone. Gone at idle speed, gone at all speeds. Unfortunately my drive to the office is only about 8 minutes so it is noisy the whole time. If I take a detour and drive longer, the noise goes away. My car does heat up by the end of my 8 minute drive, as the temp gauge gets to just below the third mark (bottom mark is first, then the next one that's 1mm or so above it, then the next one at about 8 o'clock). In San Diego it never seems to get above the 8 o'clock - only in traffic...

What do guys think? Should I start swapping out belts? (I didn't have time last night... )

Jeff Curtis

Okay, now we're getting somewhere.

When I wash my 964, I have a 3.8RS tail with open vents...just a screen in place to block the big stuff from getting in there. Of course, water, soap/suds gets down in the engine compartment when I wash it and I don't take care to avoid it, no big deal.

BUT - when I start it up, a few seconds after it starts my belts squeek for about 10seconds at the most. You see, when you start your 964, the alternator doesn't kick in right away, and when it does, there's a considerable amount of drag that sets in.

I'm thinking a fresh set of belts might help you out at this point?? You say you have tightened one of them, how 'bout the other one?

I do find it strange that one of them squeeks for your entire commute to work, so I'm guessing one, or both of your belts are "glazed" and they are slipping excessively??

That is my best guess.

phr964

Been having huge squeaky sounds coming from the engine for a number of months now. Initially it was present only while the engine was cold, and often I could eliminate the noise (at traffic lights) by revving the engine hard. It really sounded like a dead alternator or A/C compressor bearing. However, I just replaced the alternator belt last weekend and all squeaking has completely disappeared. Since I happen to have Torx tools and a 24 mm ring spanner the job only took about 20 min. If I'd known I would have changed the belt months ago...

Cheers,

Peter
------
'91 964
'98 M3

phr964

Been having huge squeaky sounds coming from the engine for a number of months now. Initially it was present only while the engine was cold, and often I could eliminate the noise (at traffic lights) by revving the engine hard. It really sounded like a dead alternator or A/C compressor bearing. However, I just replaced the alternator belt last weekend and all squeaking has completely disappeared. Since I happen to have Torx tools and a 24 mm ring spanner the job only took about 20 min. If I'd known I would have changed the belt months ago...

Cheers,

Peter
------
'91 964
'98 M3