97 Passat TDI serpentine belt tensioner replacement:

dosma

Well-known member
Joined
Aug 15, 2002
Location
Northern California
TDI
'97 Passat TDI
Can you replace the spring tensioner without removing the alt/Air mounting bracket on the B4? I'm at 97kmiles and am getting the tensioner vibration and noise.

Thanks for info.

...Don
 

redmondjp

Veteran Member
Joined
Jul 1, 2004
Location
Redmond, WA
TDI
'96 Passat Sedan
Absolutely!

First you will want to release tension by removing the serpentine belt itself. Then remove the single bolt holding the tensioner shaft to the spring (center of the spring), and finally remove the two bolts holding the tensioner spring housing to the alternator support bracket. You may have to gently tap the tensioner shaft towards the passenger side of the car in order to get it separated from the spring. You'll want to relubricate the tensioner rod shaft when you have it out--you'll probably have to remove the air filter box to get the tensioner rod all of the way out of its bracket. There are other posts here which discuss which lubricant to use on this (search is your friend).

It's been awhile since I've replaced my tensioner spring. I seem to recall having the alternator removed for easier access to it, but I don't know that it's a necessity to do so.
 

dosma

Well-known member
Joined
Aug 15, 2002
Location
Northern California
TDI
'97 Passat TDI
That's good news. I was dreading the possibility of having to remove the alternator and air compressor. Is it necessary to remove the tensioner shaft altogether or can you push it back and put the new tensioner on without removing the air filter box? The Bently is really vague about how it's mounted.

I tried several searches for information on this subject and found very little. I haven't mastered the search function on this site.

Thanks for the info.

...Don
 
Joined
Apr 27, 2003
Location
Stafford Virginia 22556
TDI
96 glx variant tdi
dosma said:
I was dreading the possibility of having to remove the alternator and air compressor.

Is it necessary to remove the tensioner shaft altogether or can you push it back and put the new tensioner on without removing the air filter box?
Both alternator and compressor are only held on by 2 bolts each. Removing either isnt much at all.

The spring tensioner often times rusts itself to the shaft so even after removing the 3 allen headed cap screws it's usually still stuck. Gently prying the two apart is all it should take. You can leave the shaft in place to do this, besides, you can't get the shaft out until you get the tensioner off.
 

rsfeller

Well-known member
Joined
Oct 6, 2008
Location
Central Ohio
TDI
1996 Passat
redmondjp said:
Absolutely!

First you will want to release tension by removing the serpentine belt itself.
Reading your post before I try to swap out my harmonic balance wheel. You first step is reduce stress on serp belt to remove. How is this accomplished? I've often remove the tensioner pulley on other cars to remove the belt. Is there a better way on the tdi?
 

rsfeller

Well-known member
Joined
Oct 6, 2008
Location
Central Ohio
TDI
1996 Passat
Yep that is what I said! :p

I went down the list of everything else but the HB, before we figured out that it is fact a common failure item. Someone told me less then an hour to DIY.

How do you go about taking the serp off for such a job? Looks pretty easy to get to. DO you just unbolt the HB and obviously the serp comes off, or take the tension off at the tension pulley?
 

RIP TDI

Top Post Dawg
Joined
Feb 16, 2000
Location
Santa Barbara, CA
TDI
'15 GSW SE 6MT...... '01 Golf GLS 5MT.... '96 Passat Variant....
rsfeller said:
Yep that is what I said! :p

I went down the list of everything else but the HB, before we figured out that it is fact a common failure item. Someone told me less then an hour to DIY.

How do you go about taking the serp off for such a job? Looks pretty easy to get to. DO you just unbolt the HB and obviously the serp comes off, or take the tension off at the tension pulley?
Untension the belt by levering the tensioner shaft with an adjustable wrench or equivalent placed on the right-angle bend of the shaft. Do not use the tensioner pulley retaining bolt as a leverage point.
 

rdkern

Top Post Dawg
Joined
May 21, 2004
Location
Humboldt Co CA
TDI
Passat 1997 silver (sold after 11 years), Jetta 2000 atlantic blue
Chris Bell said:
Untension the belt by levering the tensioner shaft with an adjustable wrench or equivalent placed on the right-angle bend of the shaft. Do not use the tensioner pulley retaining bolt as a leverage point.
I have a "pickle fork" purchased for a front-end job on my 67 bug. It's curve and set forks allow fairly easy leverage on the tensioner shaft. I didn't have any wrenches large enough to hold it easily.
 

Mrg-images

Member
Joined
Jun 2, 2015
Location
Port Charlotte, fl
TDI
1996 Passat TDI
Steve Addy thank you! Okay so the serpentine belt is the L shaped one? Alternator to the top and just below it to the left is harmonic balancer? Trying to get an understanding of what people mentioned in the comments above. I’m wondering if my HB is bad also. Not sure of when it’s been replaced. Figured I’d maybe just do it all at once.
 

Steve Addy

Top Post Dawg
Joined
Aug 7, 2002
Location
Iowa
TDI
97 Mk3
Steve Addy thank you! Okay so the serpentine belt is the L shaped one? Alternator to the top and just below it to the left is harmonic balancer? Trying to get an understanding of what people mentioned in the comments above. I’m wondering if my HB is bad also. Not sure of when it’s been replaced. Figured I’d maybe just do it all at once.

The L shaped belt is the serpentine, the triangle belt is the small V-belt that runs the PS and the WP. They both involve the crank because that's what drives them.

If you have chirping then likely that your HB is bad, especially if it's first gen type HB. That would be my first visit.

Steve
 

Mrg-images

Member
Joined
Jun 2, 2015
Location
Port Charlotte, fl
TDI
1996 Passat TDI
Thanks Steve Addy, I appreciate you. If the serpentine belt isn’t cracked or looked worn then naturally it wouldn’t squeal/chirp/make noise? I can only assume it’s the first gen HB. I think it’s the HB now listening. I was thinking chirping like bird but, it’s more like a bugs chirp from what I hear. I’m guessing when a serpentine belt goes bad it has a long squeal at start up and it’s high pitched? Goes away when warmed up, no? In the diagram where would the HB be? Anything guidance is great, thank you.
 

Steve Addy

Top Post Dawg
Joined
Aug 7, 2002
Location
Iowa
TDI
97 Mk3
Thanks Steve Addy, I appreciate you. If the serpentine belt isn’t cracked or looked worn then naturally it wouldn’t squeal/chirp/make noise? I can only assume it’s the first gen HB. I think it’s the HB now listening. I was thinking chirping like bird but, it’s more like a bugs chirp from what I hear. I’m guessing when a serpentine belt goes bad it has a long squeal at start up and it’s high pitched? Goes away when warmed up, no? In the diagram where would the HB be? Anything guidance is great, thank you.
It's rare to find serpentine belts squealing, the tensioner takes up the necessary slack and the fact that the belt is wide also makes it less likely.

The HB (harmonic balancer) is located on the crankshaft. The four allen head bolts that hold the outboard v-belt pulley also hold the harmonic balancer in place.

This topic reminds me I've been planning on ordering a new one.

Steve
 

Mrg-images

Member
Joined
Jun 2, 2015
Location
Port Charlotte, fl
TDI
1996 Passat TDI
Steve Addy, so I tackled the project yesterday. Relatively easy to do. Had a buddy help me get the belt back on and honestly that was the hardest part. I used air tools so it wasn’t much work really. I replaced both the harmonic balancer and belt, no chirping anymore. Only problem is was it the belt or the HB? Heh, I’m suspecting it was the HB. The belt wasn’t in any sort of weathered condition. Appreciate the guidance! Cheers.
 

Steve Addy

Top Post Dawg
Joined
Aug 7, 2002
Location
Iowa
TDI
97 Mk3
Steve Addy, so I tackled the project yesterday. Relatively easy to do. Had a buddy help me get the belt back on and honestly that was the hardest part. I used air tools so it wasn’t much work really. I replaced both the harmonic balancer and belt, no chirping anymore. Only problem is was it the belt or the HB? Heh, I’m suspecting it was the HB. The belt wasn’t in any sort of weathered condition. Appreciate the guidance! Cheers.
Post up a picture of the HB you removed and we'll see what gen HB it was. If it's the early one then more than likely it was the HB and not the belt.

Glad you got it done!

Steve
 

Mrg-images

Member
Joined
Jun 2, 2015
Location
Port Charlotte, fl
TDI
1996 Passat TDI
Still noise!


Okay so it went away for about a day or two. Digging deeper, I’m trying to post a picture of the tensioner arm. It has some “wear” to one side I’m not sure of and seems impossible that it could be worn. But you never know. Ordered the tensioner wheel and the cap that fits inside where the arm is, thinking it might be one of those but after removing the arm I’m questioning whether the play it has makes the noise. I mean can it wear like that over time? Seems like good strong metal. And it’s hard to find photos of the arm you just see the straight on one.

Steve Addy maybe you could shed some light for me. It’s starting to just be annoying at this point.
 
Last edited:

Abacus

That helpful B4 guy
Joined
Nov 10, 2007
Location
Relocated from Maine to Dewey, AZ
TDI
Only the B4V left
I’ll bet that is your problem. If it were me, I’d replace the entire works since it’s obviously well worn out. What happened is the seals probably let go and grit got in there and wore it out. I just hope the housing is OK.

Here is the Arm.
And the arm bushings.
And the seals.
 

garciapiano

Veteran Member
Joined
Feb 12, 2018
Location
Southern California
TDI
1997 Jetta TDI (1Z)
Your tensioner rod is pretty damn worn, I've never seen one that bad. I'd replace it to keep the belt tracking straight. In which case you need a new rod, bushings and seals.

To remove the rod, unfortunately you do have to remove the entire alternator bracket, as trying to pull out the rod you run into the frame rail, at least you do on a jetta. Not sure about the passat.

All I can tell you is that those metal bushings the rod rides on are pretty annoying to replace. I think they eventually chemically seize in place. I spent a few hours trying to get the old ones out. You basically need a super long, sharp chisel. I used a combination of cold chisels and very long, skinny nail that had been filed to a flat end to push the bushing out of the hole from the far end. A bench vise would make the job a lot easier.

Pressing in the new bushings is a bit of a chore as well. You'll want to polish up the inside of the bore before putting them in. I packed the bore up with wheel bearing grease on my car and it still feels fine.
 
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