Normal serpentine belt tensioner travel length

Andrei Rinea

Veteran Member
Joined
Jan 21, 2002
Location
Europe, Romania, Bucharest
TDI
VW Tiguan 4Motion 2.0 TDI 170HP (engine CBBB)
How much is supposed to move the serpentine belt tensioner during idle? Mine does move up and down about 10-12 mm (~ 1/2 inch). Is it in specs or is it that famous tensioner problem? How much is too much? (mm or inches)
 

RIP TDI

Top Post Dawg
Joined
Feb 16, 2000
Location
Santa Barbara, CA
TDI
'15 GSW SE 6MT, '01 Golf GLS 5MT, '97 Passat sedan, '96 Passat variant
There is no spec. If the pulley is jumping, the spring has lost tension. A solid adjusting plate is the only permanent solution.
 

dieseldorf

Top Post Dawg
Joined
Oct 11, 2000
Location
MA
TDI
ex- 1996 wagon, ex-2000 Jetta
Mine does move up and down about 10-12 mm (~ 1/2 inch). Is it in specs or is it that famous tensioner problem? How much is too much? (mm or inches)
that sounds like excessive travel and you may want to order a new one. They seem to have a lifespan of 80k miles or so before they really grow weak resulting in the bouncing.
 

Andrei Rinea

Veteran Member
Joined
Jan 21, 2002
Location
Europe, Romania, Bucharest
TDI
VW Tiguan 4Motion 2.0 TDI 170HP (engine CBBB)
What a price...

I went to Porsche today (main local VW dealer) and they quoted me 110 EUR (~120 $) for the part. What happens if I let it the way it is and don't change it? I have many different ways to spend 110 EUR. Like... 400 beer bottles (yeah... it's 27 cents a bottle - medium quality (not bad!)
 

RIP TDI

Top Post Dawg
Joined
Feb 16, 2000
Location
Santa Barbara, CA
TDI
'15 GSW SE 6MT, '01 Golf GLS 5MT, '97 Passat sedan, '96 Passat variant
They seem to have a lifespan of 80k miles or so before they really grow weak resulting in the bouncing.
I wish. I replaced mine last year and it has now just started to make 1 or 2 of the characteristic chattering squeeks during a cold morning start, the first sign of a weakening spring. Perhaps once the tensioner shaft bushings start to wear, replacing the spring unit is only a short-term cure. That's why I say the only permanent solution is a fixed adjustment plate.

Another possibility may be to try using a tensioner from an ABA (2.0l) engine. From a casual glance, it looks like it would fit, and I haven't heard that this engine is as prone to this problems as the Z1/AHU is.
 

RIP TDI

Top Post Dawg
Joined
Feb 16, 2000
Location
Santa Barbara, CA
TDI
'15 GSW SE 6MT, '01 Golf GLS 5MT, '97 Passat sedan, '96 Passat variant
What a price...

What happens if I let it the way it is and don't change it?
The constant oscillation of the tensioner shaft can wear the shaft bushings in the mounting bracket. They are part of the mounting bracket and not available separately, so you either replace the bracket or come up with your own bushings. That bracket is very expensive, compared to the tensioner unit. If and when you replace the tensioner unit, check the shaft's radial play in the bracket.

Another possible effect from the oscillating tensioner might be shorter belt life, but I wouldn't think it would be dramatically worse.
 

Andrei Rinea

Veteran Member
Joined
Jan 21, 2002
Location
Europe, Romania, Bucharest
TDI
VW Tiguan 4Motion 2.0 TDI 170HP (engine CBBB)
4 years later....
I changed the tensioner spring and the roller. Plus the harmonic balancer (ouch my wallet). All seemed ok but 6 months later (7k miles) my serpentine belt has failed.

It started making funny noises at idle and in slow traffic. I opened the hood at a red light and I got so horrified : only 1/2 of the belt was still on the car. I turned around cowardly and headed home. At 1-1 1/2 miles from home the battery light went on on my dashboard. At home (I made it!!!) there was nothing left of the serpentine left. MAINLY NOTHING!!!

All the ribs came apart and parts of them broke into smaller parts too. You couldn't simply think there was a serpentine belt there once.

HORROR.

I will be towing my car (I do have a solid bar to tow) to my mechanic for an investigation + a new OEM(!!!) serpentine belt.

The Serpentine belt was an aftermarket one but still... I cannot believe how something can eat itself so completely so fast.... It's like it was never there.

I checked my engine bay 2-3 days before this horror and NOTHING seemed problematic. No cracks no shredding no nothing. All of the sudden it happened. All the pullies are clean, aligned and rotate freely... :( . I do have the plastic mud protector (plastic "skid plate"). I can only think of the following things :

1. Bad belt - bad material etc. etc. etc.
2. FOD - Foreign Object Damage. WHAT EFFING FOREIGN OBJECT!?
3. IDK - I Don't Know


Any ideeas?
 

rdkern

Top Post Dawg
Joined
May 21, 2004
Location
Humboldt Co CA
TDI
Passat 1997 silver (sold after 11 years), Jetta 2000 atlantic blue
The serp belt over hear turns the ac and alternator. I drove 50 miles without one once (straight across desert driving - with no ac).

The reason mine snapped was the ac clutch failed - which meant an expensive stopover in Tehachapi.
 

Andrei Rinea

Veteran Member
Joined
Jan 21, 2002
Location
Europe, Romania, Bucharest
TDI
VW Tiguan 4Motion 2.0 TDI 170HP (engine CBBB)
Here (Europe) there are many versions :

1. Some acc.belt turn the A/C but don't turn the power steering
2. Some acc.belt doesn't turn the A/C but turns the power steering
3. .... (other combinations)

Practically my question in this case would be :

SHOULD I ASSUME IT WAS A BAD MATERIAL / FAULTY BELT in the first place?
 

Andrei Rinea

Veteran Member
Joined
Jan 21, 2002
Location
Europe, Romania, Bucharest
TDI
VW Tiguan 4Motion 2.0 TDI 170HP (engine CBBB)
I found the reason why the belt came apart : it was rubbing agains the timing belt lower cover.

This happened because the harmonic balancer was replaced with a "shorter one", because the lower timing belt cover was not perfectly secured and probably also because the crank was shortened (very lightly) when reconditioned.

Now my mechanic put a thicker distancer washer between the harmonic balancer and the crank sprocket and seems ok.
 
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