Tell me the symptoms of failing alternator pulley....

Let me know. List as many as possible....

If you are wondering about your alternator pulley, there is an easy test.

Remove serpentine belt
Carefully stick a screw driver into the cooling fan to hold the internals still
Rotate the pulley - it should freewheel in one direction and lock up in the other

Thanks a lot. I know that test, just wondering for more outward signs like noises, vibrations or whatever.....

someone told me once ther would be metal shavings laying around

Mine first became apparant when I taxed the power steering at idle. I felt a vibration through the car and thought my PS pump was bad.

--Nate

I was going around a curve to the left about 50 mph (warning sign indicated safe speed at 45 mph) all of a sudden the car lost power steering, the check engine light popped on (some light), etc., and I thought the guard rail had me!

To my knowledge, there was no warning at all. When I removed the Alt, the outer part of the pulley fell out onto the garage floor! That was the OEM pulley......... kaput just a little past 194k miles!

The question becomes whether these should be replaced at a regular service interval? Every TB change?

I recommend it be changed with the timing belt, what the heck, I'm already in there so why not ? I hardly ever see one at 100k miles that isn't spitting the grease out of itself or already locked up. If your serpentine belt tensioner is doing a dance at idle chances are the alternator pulley is already locked up.

When mine went, it showed intermittent battery warning light and made a squeal that could be heard at idle. When making noise, I could see the alternator slowing down. I believe the new pulleys are of better design, and so may have a longer life.

Just for understandings sake. The pulley will freeze up and not turn in either direction? So what does the belt slip around on the alternator pulley? I would imagine that creates a lot of friction and the belt would snap...

Mine was bouncy and noisy and I had already replaced the tensioner thinking it was the problem since that's where the symptom showed up.

Metalnerd makes a nice tool for the clutch pulley so nothing else really needs removed. When I researched it the "newer" design is shorter than the old one and that's what it took to make it an easier job.

Can't answer ^ question directly because I fixed mine before it froze. I've heard of belts snapping and, more commonly I believe, pulleys falling off.

My symptoms were as follows:
1. Very subtle and occasional bearing squeak at idle for a few days
2. Loud squeal at start-up twice
3. While driving, an odd clunking sound and very brief illumination of the battery light, twice

Get 'er fixed if you have any signs.

davebugs said:

Mine was bouncy and noisy and I had already replaced the tensioner thinking it was the problem since that's where the symptom showed up.

Metalnerd makes a nice tool for the clutch pulley so nothing else really needs removed. When I researched it the "newer" design is shorter than the old one and that's what it took to make it an easier job.

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So when you put a new tensioner on the symptoms remained?

For Reference

See Here:
http://forums.tdiclub.com/showthread.php?t=215955&highlight=alternator

I replaced the tensioner first too, because it was easier.

POWERSTROKE said:

So when you put a new tensioner on the symptoms remained?

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yep. Just like the above fella.

I did one a couple weeks ago. It was a new aftermarket alternator with aftermarket pulley. The car would charge normally till you blipped the throttle, then the pulley would stop driving the alternator. You could look into the alternator and see that the internal parts were not spinning, with the engine was running.

The "in the car" metalnerd tool wouldn't work on the aftermarket pulley/alternator so I had to pull the damned thing anyway.

Pulley can fail in one of three ways: 1) Lock up completely, causing belt and tensioner to vibrate. 2) Freewheel, causing batt light to come on. 3) Fall off, causing belt to come off too.

Mine did #2 at about 120kmiles.

Ski in NC said:

Pulley can fail in one of three ways: 1) Lock up completely, causing belt and tensioner to vibrate. 2) Freewheel, causing batt light to come on. 3) Fall off, causing belt to come off too.

Mine did #2 at about 120kmiles.

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__. My car ('03 Jetta wagon) was the "fall off in the belly pan" failure mode; MzLauraLee's was noise from the serp belt tensioner with visible tensioner "bouncing". Tom ("Ninedee_golf_TDI") was doing her timing belt at the same time; found the alternator pulley locked up solid. He replaced both and that did the trick.

On an '06 Jetta with 80K miles, I had metallic squawk on cold start-up that went away after warming up. Eventually the noise got worse with the tensioner bouncing symptom. I replaced in car in ~1/2 hour.

Mark of Diesel said:

metallic squawk on cold start-up that went away after warming up. Eventually the noise got worse with the tensioner bouncing symptom.

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same here. I had the belt, tensioner, and alternator pulley replaced. the noise got quieter and less frequent but it's still there. now I'm thinking a/c compressor?

ryanhorlacher said:

same here. I had the belt, tensioner, and alternator pulley replaced. the noise got quieter and less frequent but it's still there. now I'm thinking a/c compressor?

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__. Is the "metallic squawk" coming from the serp belt/ pulley area? There is also a nasty-sounding squawk that comes from the starters on many VW models; it's not a sign of impending failure like the pulley (and can be fixed by cleaning and lubing the engagement mechanism on the starter) but it sounds really bad. Something to check before you get focussed on the serp belt area. Replacing the pulley and tensioner usually solves the problems in that area -- is the belt still "bouncing" or does the tensioner sit smoothly on the belt? I guess there's a chance that you got a bad pulley or tensioner when you replaced them. But something is definitely different from most peoples' experience with your car.

POWERSTROKE said:

The question becomes whether these should be replaced at a regular service interval? Every TB change?

Click to expand...

In my case, no. The alternator pulley failed BEFORE the timing belt change interval. By about 6000 miles before.

--Nate

Alt pulley

POWERSTROKE said:

Just for understandings sake. The pulley will freeze up and not turn in either direction? So what does the belt slip around on the alternator pulley? I would imagine that creates a lot of friction and the belt would snap...

Click to expand...

The "clutched" Alt pulley is to protect the Serpentene belt from the sudden stop when the engine is shut off (the alt internals keep turning, thus the "over-ride" affect of the pulley).

If the "clutch" locks up, the Alt will still rotate. However, most likely it will "wobble" be "out of round" etc., causing vibrations which will also cause the tensioner to be bouncey!

I replaced the pulley on my brother's car back in September, at about 200k miles....... the old one "seemed" fine! (As I posted previously, mine died at about 194k)

Just based on my very limited experience, 200k miles seems to be about average to go kaput!

mrGutWrench said:

__. Is the "metallic squawk" coming from the serp belt/ pulley area? There is also a nasty-sounding squawk that comes from the starters on many VW models; it's not a sign of impending failure like the pulley (and can be fixed by cleaning and lubing the engagement mechanism on the starter) but it sounds really bad. Something to check before you get focussed on the serp belt area. Replacing the pulley and tensioner usually solves the problems in that area -- is the belt still "bouncing" or does the tensioner sit smoothly on the belt? I guess there's a chance that you got a bad pulley or tensioner when you replaced them. But something is definitely different from most peoples' experience with your car.

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definitely not the starter, just a few weeks ago I put in the 3rd new (reman) starter since the 01m delete in July. the first two were duds, this one seems to be holding up fine.

the sound is definitely on the serp belt side, definitely changes its frequency along with engine speed, and the tensioner isn't jumping around anymore. I can hear it better from the top near the alternator and ps pump than from the bottom near the ac compressor. I suppose it could be a bad part just like the starters were... any chance it could be on the timing belt? I should have another 40k miles before it needs replaced, but I did (carefully) use non-tty bolts to adjust timing a while ago.

AndyBees said:

If the "clutch" locks up, the Alt will still rotate. However, most likely it will "wobble" be "out of round" etc., causing vibrations which will also cause the tensioner to be bouncey!

I replaced the pulley on my brother's car back in September, at about 200k miles....... the old one "seemed" fine! (As I posted previously, mine died at about 194k)

Just based on my very limited experience, 200k miles seems to be about average to go kaput!

Click to expand...

replaced mine at ~230k miles. the squawk probably started around 210k. (yes, I'm probably far more tolerant of bad symptoms than I should be). I didn't notice if the tensioner was bouncing when the sound started but it definitely was when I had it replaced. the car came with complete service records and there's no indication of the alternator pulley or belt tensioner being replaced before.

Mine locked up at 82k, I tried replacing it, but all I had was the 12pt triple square bit and not the splined tool.

I put a big pair of channel locks on the pulley and tried to turn the shaft with the 12 pt bit. The pulley broke lose and started free wheeling again. Not it rattles some times, and sometimes it's normal.

I have the tool on order..LOL.

The pulley can fail early so doing it at timing belt may not be the option. I didn't mine at about 70K miles so I wasn't going to change it again at 100K miles. They aren't that hard to do and they don't blow up most of the time without warning. Mine was hopping at idle. Also the battery light was going on and off at times. I rent the tool for $12 shipped and I have a pulley for sale with the tool rental shipped for $69. Not a crazy deal but no waiting on availability, paying separate shipping, etc. Plus if no one buys it I have a spare for when mine goes again or my brothers goes out. I have two tool sets (old and new style). For the record it use to be $5 plus shipping but by the time I get deducted from paypal, the shipping and things like that it is basically $12. Not really making money off it.

I am amazed how many people change the tensioner first. I don't think it has ever been the root of the problem from the posts I have read so far. Anyone out there where that failed first?

My 2005 Beetle TDI had a bad alternator pulley. The symtom was a shuddering when turning the steering wheel at idle. I had it replaced and got a 5 mgp uptick in fuel economy. I have only had the car for 3 weeks and am now on my 3rd tankful, got 510 miles on it and got scared, thinking the fuel gauge had quit working, and only put in 11 gallons. Think I will try for 600 miles on this tankful and I guess I had better update my profile MPG.

Huh. The best I can describe the noise mine was making was like a fan blade hitting a metal sheath or the rattle of ball bearings. Sometimes it'd do it, sometimes it'd be quiet.

When it was noisy the alternator was spinning noticeably slower. And of course the previously mentioned occasional battery light flicker.

Strange though, I never got any shimmy or shaking when turning, or squeals on startup or odd vibrations.

Didnt read the rest of the thread.. but if your car only charges while giving it throttle, the pully could be going