Alternator pulley or tensioner?

My 2004 Jetta (BEW engine) makes a horrible noise when I turn the steering wheel at low RPM. In addition, the belt tensioner was really vibrating, probably a 1/2 inch or more. I read many posts about the alternator pulley being the most likely problem. When I checked the pulley operation by sticking a screw driver through the housing to prevent the fan from spinning, it would not move in either direction. So I guess the clutch is frozen? Most of the other posts described a problem with the pulley where it would turn in both directions, so not what I am seeing. Anyway, I went ahead and ordered a new pulley and the newer tool from IDParts (one piece tool). Unfortunately, someone before me must have tried too hard to get it off in the past, because the toryx bit would not hold. I removed the alternator and can see that the splines on the nut holding the pulley on are almost gone (the toryx driver gets stuck in there when I turn it much at all).

So my question is whether this type of pully problem would result in the tensioner virbrating so severely, or is it the tensioner itself? Other than the belt/tensioner vibrating, and the horrible noise when turning the steering wheel, I was never getting any signs that the alternator wasn't working right.

Yes, the locked pulley will cause the tensioner to bounce, and eventually it will fail.

I think the noise when you turn the wheel is unrelated. Have you checked your power steering fluid level?

Agree with Indigo.

And you may need to trade in the alt as a core due to not being able to remove the pulley.

My AAZ engine stock didn't have a clutched pulley and it made a lot of noise at idle. I put a clutched one on and it is MUCH better. And that is one of the theories of the crank sprocket failing (larger alternator then past cars+more rotational mass speeding/slowing with the engine pulses).

Good luck.

Hey. Thanks for the fast response. Yes, that's what I first thought it might be, but the fluid is full (up to max line). I thought the power steering pump could exert enough resistance to make the belt screech - the belt being lose (sometimes) because of the tensioner bouncing. Any other suggestions.

Also, looks like I'm gonna have to replace the alternator, since I can't get the pulley off. I wonder if IDParts will let me return the new pulley and tool if I buy the alternator from them.

charlie_s said:

Hey. Thanks for the fast response. Yes, that's what I first thought it might be, but the fluid is full (up to max line). I thought the power steering pump could exert enough resistance to make the belt screech - the belt being lose (sometimes) because of the tensioner bouncing. Any other suggestions.

Also, looks like I'm gonna have to replace the alternator, since I can't get the pulley off. I wonder if IDParts will let me return the new pulley and tool if I buy the alternator from them.

Click to expand...

Likely they will, at least the unused pulley. Call em sometimes better than email.

The bad pulley will rattle just like a bad DMF just on the other end. I had a bad override clutch on my alternator pulley that make a lot of noise. My DMF was failing as well with similar symptoms.

Yes a bad alt pulley can cause your serpentine belt to slip/chatter at the power steering pump.
Change the alternator but make sure that you get one for a tdi so it has a clutched pulley.
It may be that someone previously installed an un-clutched alt from a gas car....causing you current issues.
If the tensioner has been vibrating for a while it will likely need changing too.
Also check all other pulleys in the system for smooth operation while the belt is off.

For what it is worth, in an emergency situation, I installed a gasser 90amp (vs TDI 120amp) Alt with over-ride pulley, on my 2000 TDI Jetta a few years back. I never did get around to installing a replacement 120amp Alt. Today, and over 50k miles later, it is working just fine. ....... not recommending, just sharing an experience!

Any updates?