Accessory belt tensioner... adjust or replace? - Troubleshooting - VWDiesel.net The IDI, TDI, and mTDI source.

• Accessory belt tensioner... adjust or replace? by addautomotive on 20 Nov, 2006 07:31
• My accessory belt tensioner skips and dances at idle. It makes the car vibrate and sound like crap, and it's making wifey unhappy. When Wifey is unhappy, I'm unhappy.
  
  I can't say I've ever even looked at it closely...can it be adjusted, or do I just need to swap it out? They run about $70. Looks like an easy weeknight project. Anything I need to know before I jump into this?
• #1 by QuickTD on 20 Nov, 2006 07:42
• Get a one way clutch alternator pulley, problem solved and the crank nose will thank you.
• #2 by addautomotive on 20 Nov, 2006 07:48
• I was wondering about that. My crank was redone with a TDI crank pulley before I bought it, so I'm not so worried about that issue.
  
  Its really about the racket. My father in law's 94 got a new tensioner and now it's sweet and quiet. He just has the standard alternator pulley.
  
  Unless I could get a used clutched pulley, I'd like to just swap out the tensioner. Mine used to be nice and quiet but now it's gone to crap.
• #3 by QuickTD on 20 Nov, 2006 08:12
• To properly fix the tensioner the big cast bracket needs to be replaced. The racket is caused by worn bushings on the tensioner shaft. The new spring cartridge has some friction and a bit more pressure that damps out the vibration for a short time. The tensioner will still "dance" with a new spring it just won't make noise. The permanent fix is the alternator pulley. It stops the "dancing" completely, the accessory drive will run dead smooth. It'll make it quiet in spite of all the other worn components and it will prevent further wear. Pretty much the same money as the spring (from roseland) and much, much more effective.
• #4 by addautomotive on 20 Nov, 2006 09:05
• Sounds like I should go that route then, thanks for the headaches you've probably saved me.
  
  Is there a part number for this fancy alternator pulley? I'll order it through the local VW dudes, unless someoen here has them available.
• #5 by QuickTD on 20 Nov, 2006 09:32
• The pulley part number is 028 903 119AA. I'm assuming you have AC and the 90amp alternator or you wouldn't be having this problem, so it should fit. Altrom lists it for $109, Brian Harrison (Roseland technical services, http://www3.ns.sympatico.ca/roseland/AutoParts.htm) is near you (NS) and can likely get a good break on that price. He's an excellent guy to deal with in Canada for VW parts. Ships promptly by mail and has great prices on OEM quality parts.
• #6 by addautomotive on 20 Nov, 2006 10:14
• QuickTD, you're a pro. Thanks for pointing me in the right direction! Is the pulley difficult to change, or do I need to bring it to a shop to have it swapped?
  
  Now, how about diagnosing my wonky idle? Idles at 1100 once warmed up, but if I go for a jaunt on the highway it'll idle a bit rough at 850. I'm thinking the fuel filter is bad and so I'm drawing a bit of air, but I don't see any bubbles.
• #7 by addautomotive on 20 Nov, 2006 10:21
• Hey, another thing QuickTD,
  
  I have that box of K03 bits... a couple housings and assorted bits & pieces from 2 bad turbos.
  
  Plus I have a partial kit from Jake Russel for a KO3. The bearings are there but the little ring that goes in the shaft is missing.
• #8 by Jetta Fan on 20 Nov, 2006 10:40
• In talking to the guy that does my alternators and starters, you need a special tool (or at least it's easier) to install the new pulley.
• #9 by addautomotive on 20 Nov, 2006 12:24
• Special too, eh?
  
  Sounds like a job for vice grips & hard liquor!
• #10 by QuickTD on 20 Nov, 2006 15:02
• Quote from: "addautomotive"

  QuickTD, you're a pro. Thanks for pointing me in the right direction! Is the pulley difficult to change, or do I need to bring it to a shop to have it swapped?

  
  
   The easiest way to get the old pulley off is to use an impact wrench. You can reach it with the alternator on the car if you pull the airbox. I wouldn't worry too much about the special tool, hold the shaft with an 8mm allen key and spin the pulley on with a strap wrench, it'll hammer itself tight. You'll need the special tool if you ever want to remove it though.
  
     
  

  Quote

  
  Now, how about diagnosing my wonky idle? Idles at 1100 once warmed up, but if I go for a jaunt on the highway it'll idle a bit rough at 850. I'm thinking the fuel filter is bad and so I'm drawing a bit of air, but I don't see any bubbles.

  
  
  You need to turn back out the "residual" screw, this is the one that the main throttle lever rests against at idle. Turn it out (counterclockwise) until the idle stops decreasing or reaches ~800rpm, then reset your idle using the idle screw on the little idle control lever at the back of the pump.
  
  I think I've got the K03 thing covered, but I can always use more parts. PM me with details, I might be interested...
• #11 by Jetta Fan on 21 Nov, 2006 03:30
• Quote

  addautomotive Posted: Mon Nov 20, 2006 4:24 pm    Post subject:  
  
  --------------------------------------------------------------------------------
   
  Special too, eh?
  
  Sounds like a job for vice grips & hard liquor!
   

  
  
  That's the special tool I was referring to.  :wink:
  
  QuickTD, thanks for the link. He's not that far from where I live (40 minuts or so).
• #12 by ibmserf on 12 Mar, 2007 09:34
• This is definitely worth the fix...only took 30 mins and made a HUGE difference!  Thanks to all for the tips.