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General Information => Troubleshooting => Topic started by: addautomotive on October 18, 2006, 02:26:55 pm

Title: 1.9 aaz engine vibration
Post by: addautomotive on October 18, 2006, 02:26:55 pm: When My car is idling, the serpentine belt tensionner bounces around and the motor seems to vibrate a fair bit. If I bump the idle up to 1000 rpms, it goes away. I have changed the tensioner wheel, but do I need to increase the tension?

FWIW, the crank pulley runs straight & true... that's not the issue.
Title: 1.9 aaz engine vibration
Post by: insdtanoodles on October 18, 2006, 03:36:58 pm: got that clutched aternator pulley? When I replaced the standard pulley with a one-way clutch pulley on my alternator pretty much all my engine vibration went away at idle and the tensioner stopped bounching around on me.
Title: 1.9 aaz engine vibration
Post by: addautomotive on October 19, 2006, 04:57:34 am: Really? How much do they cost?
Title: 1.9 aaz engine vibration
Post by: Jetta Fan on October 19, 2006, 05:22:41 am: When my tensioner pulley flew apart a few weeks back, the guy I got the part from told me to check my belt when I put it back together and if the tensioner was bouncing or vibrating, I needed a new tensioner.

What's this one way clutch pulley? What does it do and what are the advantages? I have never heard of one.
Title: 1.9 aaz engine vibration
Post by: QuickTD on October 19, 2006, 06:07:34 am: Quote
What's this one way clutch pulley? What does it do and what are the advantages? I have never heard of one.

The one way clutch pulley only allows the alternator to be driven forward, the pulley freewheels the other way. The pulley stops the inertia of the alternator from backdriving the belt when the crankshaft speed is fluctuating, as it is when the engine is idling. It will completely eliminate the tensioner pulley bounce common to all AAZ engines and may help preserve the fragile crank pulley key.

The pulley is a standard part used on the TDI (028 903 119AA) and will fit the 90A AAZ alternator without modification. The cost is about $100 from the jobbers, might be cheaper now, I haven't bought one in a while. You need a special tool (spline wrench) to install it. Any auto-electric outfit would probably have the tool, they might even have the pulley. "Metalnerd" on TDIClub sells a tool as well.
Title: 1.9 aaz engine vibration
Post by: Jetta Fan on October 19, 2006, 06:27:53 am: Thanks for the info QuickTD. I'll have to look into getting one in the near future.
Title: 1.9 aaz engine vibration
Post by: addautomotive on October 19, 2006, 07:42:06 am: Interesting stuff... I notice the vibration is wose when I laod teh alternator. I use a 12v heater for vegetable oil that draws ~15 amps, when that comes on it really vibrates, even if the idle is up.

I'll have to ask about the pulley. Any of our members carry them?
Title: 1.9 aaz engine vibration
Post by: A Guy on October 19, 2006, 08:07:35 am: I'm interested in this too. Is there a memeber that stocks/sells them? If not what about a group buy?
Out.
Title: 1.9 aaz engine vibration
Post by: A Guy on October 25, 2006, 02:48:26 pm: anybody??
Title: 1.9 aaz engine vibration
Post by: insdtanoodles on October 25, 2006, 03:37:59 pm: Quote from: A Guy
anybody??

you can get them from altrom www.altrom.com and its part number 028903119AA.
Title: 1.9 aaz engine vibration
Post by: jimbrown618 on October 26, 2006, 04:52:10 pm: Just to get this straight, the stock pulley is not a one-way tensioner & the replacement TDI one is? Cheers.

Jim
Title: 1.9 aaz engine vibration
Post by: SMOKEYDUB on October 27, 2006, 10:34:24 pm: is your crank pulley wobbling?
Title: 1.9 aaz engine vibration
Post by: LeeG on October 28, 2006, 12:06:58 am: Can someone describe hw much wobble is too much wobble?
I was looking at a cheap '94 Golf 1.9TD last week. 260,000 km on the clock. The serpentine tensioner was bouncing about 1/8". There was no visible wobble in the serpentine pulley, but it was hard to see. The Vbelt pulley for power steering had about a 1/16 axial wobble, no radial wobble I could see.

Does that sound good, bad or otherwise? I know the real fix, but I would rather not get one that is already messed up. I was going to lowball the guy, but someone else bought it that night for full price.
Title: 1.9 aaz engine vibration
Post by: addautomotive on October 28, 2006, 12:21:05 pm: Quote from: SMOKEYDUB
is your crank pulley wobbling?

Nope, crank pulley was fixed before I bought the car
Title: 1.9 aaz engine vibration
Post by: flash319 on October 29, 2006, 09:29:26 am: I just fixed that problem on my AAZ Jetta. I put on a new tensioner and problem gone. $65 online at autopartonlinecanada.com. The spring must get weak just in that range of motion.