ALH Serp. Tensioner Damper Failure w/ pics and video

[STRANGETDI]

Hi all,

As I was doing my oil change today, I noticed all these tiny shards of metal all over the engine. It took me a little while to figure out what is was, but I found the source. It looks like the bolt/mount that the serpentine belt tensioner damper is attached to, snapped off and is vibrating all over the place when the engine is running. The broken part is rubbing against the pulley wheel and the shards are coming from both the pulley and the broken bolt/mount atached to the damper. I also saw that my coolant hose is being rubbed against and is slowing wearing away, as I can see the threads in the hose.

So I guess my question is:
Is my tensioner still OK, and what is the purpose of the damper.?I don't beleive I can reinstall it or a new one as the mount on the engine is broken off.

See pics of metal shards and busted damper:

Below you can see the coolant hose threads showing, just above the tensioner damper/piston thing.

this picture shows the break of the two pieces where the two pieces meet.

In this pic you can see that the side of the pully wheel is what is being rubbed against, by the broken mount attached to the damper. This is where the shards are coming from.

This is a pic with the engine running, I have a few videos but don't know how to post them here.

So what do you guys think?
So I guess my question is:
Is my tensioner still OK, and what is the purpose of the damper? I don't beleive I can reinstall it or a new one as the mount on the engine is broken off. (update: it's not a broken engine mount.)

What should I do? The tensioner, damper and belt was replaced about a year ago by my mechanic. I wonder if he tightened the bolt to much that caused it to snap at the time or recently? Or something else? Car has 210,000 miles on it. Is the car driveable with out the damper? It seems so as it looks like it has been like this for a while now.

 

[joetdi]

I think your alternator pulley is seized and it raised hell with the tensioner.

 

[STRANGETDI]

You think? All pulley wheels and sprockets appear to be spinning normally.

 

[dadsdiesel]

Your tensioner is broken - the mount broke where the tensioning piston bolts to the body of the tensioner. This is not where the tensioner mounts to the block.

Here is a photo of what it should look like:

http://www.metalmanparts.com/product.sc?productId=106&categoryId=-1

Your tensioner needs replaced and you also need to find out why it broke in the first place. A good place to start is to test the alternator pulley as joetdi suggests.

 

[AndyBees]

Although your cicumstances may be different, but that's why I thru my engine cover in the garbage 8 years ago. And, at each fill-up, I pop the hood and take a peek underneath!

I believe dadsdiesel hit the nail on the head!

The Damper/Tensioner is to take out the slack in the Serpentine Belt and maintain a smooth rotation. If the Belt fit perfectly without the Tensioner assembly it would be very difficult to remove/replace. Remember the days of a V-belt and using the Alternator as the device to "tighten" the belt(s)?

 

[STRANGETDI]

I did the same with my engine cover many years ago too.

Glad to see the image of the whole assembly. Thanks. New tensioner and belt will be on order.

 

[Growler]

you will want to put one of those coolant hoses on order as well.

impex has it for $29 plus shipping.

I just had to replace this hose on my wagon as well due to a broken dogbone and the radiator fans cutting it..

its no fun, but not difficult to do.. you just get to take your whole core support off of the car to get at it...

1J0-121-109-C is the part number for that coolant hose.

 

[STRANGETDI]

I found my receipt for the serpentine belt and tensioner work, and it was replaced 10 months ago today, mileage wise is just a hair under 20,000 miles. Should I have a conversation with my mechanic about this? My wife seems to think I don't really have a leg to stand on in terms of having some of this replaced at his cost.

Also should my parts list consist of: tensioner, belt, the affected pulley (seems ok but not sure), coolant hose? Any new bolts that I need or can the existing be reused? Is that everything?

 

[AndyBees]

Tensioner/Damper with roller is purchased as a unit. The Serpentine Belt is a separate purchase also..........in otherwords, they do not necessarily come as a package deal. Therefore, if the mechanic only replaced the belt he would not have "unbolted" the Tensioner/Damper to do so! The Tensioner/Damper is "spring loaded" and must be "moved" using either a 15 or 16mm wrench (at the moment, cannot remember which) in order to relieve the tension to remove/replace the belt. The assembly actually has a hole to stick a pin to hold the Tensioner in an "off belt" setting while you do the work. ........wrench relieves the pressure and then remove the pin and the tensioner is let back down on the belt.........no Rocket Science involved at all!

But, if the dude did in fact replace the Tensioner/Damper or remove it for some reason and did not properly bolt it back on.......well, a bolt could have broke or worked loose. There are three of them (bolts).

Hope this helps!

 

[STRANGETDI]

Andy, both the belt and tensioner were replaced. Thanks for your input.

If the alternator pulley seized and snapped this thing, how did it seem to unseize itself and begin freely spinning again? Should the alternator be looked at again?

I may have to drive this thing a little bit. Even if it is to get it to my mechanic. I may cut the damper thing off with a hack saw so it's not banging all around like it has been for some time.

Also on a related note, I got the tensioner and belt replaced 10 months ago because of this:

http://forums.tdiclub.com/showthread.php?t=287259

So maybe Alternator pulley or A/C Compressor? FYI, I have not once touched the A/C controls since he thought it might be bad.

 

[AndyBees]

Unless you have a lot of miles to travel, say over 50, you should be able to drive to your mechanic without the Serp belt. Of course, there will be no Power Steering assist or Alt for keeping the battery up. If the Daylight Driving Lights are on, the distance will be especially limited.............turn off AC, dash fan, radio, use brakes all as necessary, and the same with signal lights. Those measures will keep the battery up!

I've driven a little over 50 miles without the Serp Belt with the DRLs on!

I'd just remove the belt and not be doing any hacksawing!

The three bolts that hold the Tensioner/Damper go into the Aluminum Bracket that holds all the accessories...........IP, PS, Alt and AC pump. The mechanic may need to "re-thread" those bolt holes..............just saying without seeing!

 

[alphaseinor]

The alternator pulley will spin one way only, you should take your belt off and try to spin the alternator back and forth with abrupt stops to see if the pulley isn't seized. It will spin the alternator freely, but it should only spin it one way under load.

 

[sgtpopeye43]

About a year ago I was driving around town, heard a clunk up front and the alt light came on. I stopped and checked under the hood and found the serp belt not moving while the engine was running. Got home and found the alt pulley/clutch laying in the belly pan. 90,000 miles on car at that time. I bought a new alt clutch/pulley and the tool to remove it but I had to remove the alt to get the remains of the clutch off. Replaced the serp belt at the same time, no problem with the tensioner.
I took a 16 MM combo wrench with an extension on it under the car to swing the tensioner to get the serp belt on. No problems since.
I'm not sure why the alt pulley has a clutch, first time I've seen this configuration. 03 Jetta TDI Wagen auto trans.
sgtpopeye43 in CT

 

[cevans]

The alternator pulley will spin one way only, you should take your belt off and try to spin the alternator back and forth with abrupt stops to see if the pulley isn't seized. It will spin the alternator freely, but it should only spin it one way under load.

^ Exactly.

If the pulley doesn't have the one-direction freewheel then it will cause the serpentine belt to vibrate/snap back and forth, and a failed Serpentine Belt Tensioner is the first victim of an Alternator Pulley failure.

 

[STRANGETDI]

Thanks all. Does that mean a new alternator or new alternator pulley or both? What is the pulley that the damper is rubbing against causing all the shards?
Part numbers?

I'll see if my brother in law (ASE cert. mechanic, who did not do the orignial tensioner and belt work, and lives 40 miles away) and I can tackle all this in my driveway (no garage) this weekend, as I don't want to drive this thing if I don't have to. I hear the place that did the work hates to work on VWs, but generally does good work and are honest. They have done other things in the past for me and did a good job.

I am trying to get all the possible part #'s I will need, pulleys, hoses, belts, alternator, A/C compressor, etc., just in case he determines what we should and need to do.

My wife and I have two long trips planned this summer and I need a solid working car. We don't want to take her car.

 

[PDJetta]

I can assure you that the alternator pulley failed first by no longer clutching. It is a clutched, one way, pulley that dampens the idle pulses of the engine on the serpentine belt. When the alternator pulley fails by locking solid on its shaft, all you will notice is that the belt tensioner vibrates ALOT when the engine is idling. This beats the crap out of the tensioner and then it fails. No odd sounds either, so if you do not observe the vibrating tensioner, you will not have a clue the alt. pulley failed.

Failures begin to show up at about 80,000 miles and by 150,000 miles the majority have failed. This is a HIGH failure item. The replacement pulleys are improved, I think. They are of a different metal. Your mechanic did not cause this problem (in my opinion).

You need to replace the belt tensioner, belt, coolant hose, and the alternator pulley. Other than the timing belt, there is only the serpentine belt (there are no other accessory belts).

The alternator pulley and special tool needed to get it off are available from here:

http://idparts.com/catalog/product_info.php?cPath=123_129&products_id=1118

AND

http://idparts.com/catalog/product_info.php?cPath=123_129&products_id=564

IDparts has the belt and tensioner and probably the coolant hose too.

PS, the pulley and tensioner can be replaced WITH the alternator installed in the car. A 16 mm (or a 5/8) open end wrench levers the tensioner to loosen the belt (I use a cheater bar on the wrench, it takes a good pull) and a big nail locks the tensioner in the "released" position (there are two holes to line up and then the nail or a drill bit or allen wrench is inserted into the holes on the tensioner)

--Nate

 

[will24]

Mine did the same thing (got your PM) and the alternator pulley was my failure as well, I did the p/s pump pulley, alternator pulley, belt and tensioner assembly. Quieted the engine down quite a bit!

-Will

 

[STRANGETDI]

Considering that my car is at 210,000, should I replace all these pulleys, the actual alternator (do they go bad) and A/C compressor(when it turns on, I get conditioned air, but I get a rattle/clicking sound that proportionally increases with engine speed)?

Time for a new car?

 

[dadsdiesel]

No need for a new car yet!

If the A/C works don't touch it.

The rattle sound that you've been hearing is probably the alternator pulley going bad and/or your tensioner bouncing around.

Before you do anything else, please test your alternator pulley. Stick a screwdriver into the fan portion of the alternator to hold it still, then turn the pulley in both directions. You should be able to turn the pulley in one direction, and not turn in the other. If it doesn't turn in either direction, then the pulley is bad and that is the likely cause of your tensioner breaking apart.

While changing the tensioner, I would replace the idler pulley also - easy to get at and not too expensive.

You can change the whole alternator if you want, but if it is just the pulley being bad, it is much easier to change the pulley on the car rather than change out the alternator.

Check the alternator pulley - replace if bad
Replace idler pulley
Replace tensioner
Replace serp belt.

 

[josh8loop]

Thanks all. Does that mean a new alternator or new alternator pulley or both? What is the pulley that the damper is rubbing against causing all the shards?
Part numbers?
I'll see if my brother in law (ASE cert. mechanic, who did not do the orignial tensioner and belt work, and lives 40 miles away) and I can tackle all this in my driveway (no garage) this weekend, as I don't want to drive this thing if I don't have to. I hear the place that did the work hates to work on VWs, but generally does good work and are honest. They have done other things in the past for me and dis a good job.
I am trying to get all the possible part #'s I will need, pulleys, hoses, belts, alternator, A/C compressor, etc., just in case he determines what we should and need to do.
My wife and I have two long trips planned this summer and I need a solid working car. We don't want to take her car.

I wouldn't do the tensioner and belt without doing the alt pulley too especially if it hasn't been done before. Ask me how I know I'll tell you anyway......I once replaced my tensioner and serp belt thinking the tensioner was the main thing that was bad. A few months later my new tensioner was trash. After scratching my head about it a bit I did some research to find out what the deal was. Like mentioned above, the tensioner is the first victim of a bad alt pulley. Make sure you get the kind with the one-way function and not just a solid pulley as alternator shops like to recommend.

 

[STRANGETDI]

The rattle sound that you've been hearing is probably the alternator pulley going bad and/or your tensioner bouncing around.

But why did the noise occur only when the A/C was on and the engine was revved?

The rattle sound was prior to the belt and tensioner being changed 10 months ago. I went to my mechanic to ask about the sound and demonstrated it for him with my car running. I left the car there for them to check it out. After work, I picked up the car and that's when he told me that he felt it was the tensioner and the belt. After replacement, the noise was still present and he stated that it's the A/C compressor.
Since money is an issue. I told him that I would wait on that. I haven't touched the A/C since.

If that goes bad does that also put stress on the tensioner to snap it? So I am sort of torn between alternator pulley and a/c compressor, but feel it may be the alternator pulley based on all your comments and experiences.

I also don't want to keep throwing parts at it either, but will get to the bottom of it.

I also saw this alternator with a non-clutch pulley that I found interesting and made me wonder if I should get a whole new alternator.

http://forums.tdiclub.com/showthread.php?t=146580&page=3

Another question I have is about the coolant hose: When replacing coolant hoses, It is ok to reuse the fluid (I do have some new fluid as well), but maybe , is there a problem getting air into the system or does it work itself out as it circulates through the coolant reservoir? Or how do you get it out?

Thanks dadsdiesel and others. Please keep the comments and suggestions coming as it will be a few days before I get to this and for the parts to arrive.

I wish I had a garage....lots of rain here in CT.

 

[dadsdiesel]

It very well could be A/C compressor, but.....to make the tensioner break itself apart like it did, there has to be a bad pulley somewhere in the belt path.
The A/C puts a good load on the belt - this extra load could very well cause the alternator pulley to act up to where you are hearing it.

I could also be way off base here.

And I know what you mean about just throwing parts at it!

I had a noise in my serp belt path - changed the alternator pulley - still there. Changed the tensioner and idler - still there. Finally I used a stethoscope and listened to each component and found that the bearings inside the alternator were bad. A long 2 weeks and a lot of money.....

Too bad you aren't near me - I have a known good alternator pulley and the tools to change it - we could change the pulley and see if your noise is still there without buying a new one.

One thing that we all seem to be in agreement with here - something other than the tensioner made the tensioner fall apart.

Since you are looking at this stuff, this is the alternator you would need if you were to replace that - it has the clutched pulley with it:

http://www.metalmanparts.com/product.sc?productId=309&categoryId=-1

And here is just the pulley:

http://www.metalmanparts.com/product.sc?productId=317&categoryId=-1

Now keep in mind - changing the alternator in these cars is no easy task - it took me over 2 hours my first time - 1.5 hours on my second one. A shop might charge you $200 or more just for labor - it isn't easy to get at and lots of parts need to be removed to get to it.

As far as the coolant hose - catch what coolant you can in a clean container, filter it through some cheesecloth or coffee filter and reuse it since it is pretty new - The air will work itself out - you just need to watch you coolant lever for the first 10-20 miles very closely.

 

[AndyBees]

Alt removal can be challenging, no doubt.

First, remove the right fan assembly which will allow more room to work (three Torx screws). I generally just pull the fan wiring loose from its attachments and then swing the assembly over toward the left front wheel and tie it back out of the way. I use a piece of cardboard to protect the Rad after removing the fan assembly (that will be obvious).

Next, remove the two bolts from the AC Compressor and then work it out of its mount allowing it to swing down out of the way. You may want to tie it up to take the weight off the pipes.

You may need to tie back other hoses to allow "elbow" room while working in such tight places...........just a suggestion!

Now, you should have ample room to get the Alt out after you have unbolted it!........one hour job at tops, including replacing the Tensioner assembly and Serp belt!

I just hope none of the Tensioner mounting bolts are broker or bolt holes wallered out! Remember, it is bolted to the mounting bracket for the IP, PS, AC, etc.

Don't forget to remove the ground wire from the Battery...........safety when working with the Alt (that big wire on the Alt is hot)!

Doesn't one of those damaged lines (Coolant) go to the Power Steering reservoir???

 

[STRANGETDI]

Can some one provide the proper torque settings for the following:

Tensioner to engine
Idler Roler
Alternator Pulley: 59 ft-lbs?

What else am I missing?

 

[procupine14]

I hear the place that did the work hates to work on VWs, but generally does good work and are honest.

This would be my cause for running away immediately. I'm sure that they had no clue that the alternator pulley is clutched at all.

This is almost the only explanation for a tensioner to go bad in the first place.

I had the alt pulley sieze on mine but not all the way. It would begin functioning correctly if you pulled off the belt and messed with it for a little while and would then sieze up a few days later. I changed out the pulley myself with the proper tool and about 30 minutes of free time.

Unfortunately, I had to get back in there and swap out the tensioner a few days later as I found that the pulley had beaten it to death and it was vibrating pretty badly.

 

[dadsdiesel]

Can some one provide the proper torque settings for the following:

Tensioner to engine
Idler Roler
Alternator Pulley: 59 ft-lbs?

What else am I missing?

Found 2 of them in the Bentley:

Idler 18 ftlb
Tensoiner mount 18ftl

Couldn't fine the alternator pulley.

Edit: found this for the pulley - looks like you are right with 59 ftlb:

http://forums.tdiclub.com/showthread.php?t=259981&highlight=alternator+pulley+torque

 

[benIV]

Can some one provide the proper torque settings for the following:

Tensioner to engine
Idler Roler
Alternator Pulley: 59 ft-lbs?

What else am I missing?

I've got 18 ft-lbs for the serpentine tensioner (13 mm)(m8x45mm in bentley)

is the idler referred to as a "relay roller" in the bentley in the generator overview?

there are two bolts holding down the alternator to the bracket that are listed at 18ft-lbs,

where did they get the 59ft-lbs for the clutched pulleys from?

 

[benIV]

What is the pulley that the damper is rubbing against causing all the shards?

Power steering pump.

 

[STRANGETDI]

It very well could be A/C compressor, but.....to make the tensioner break itself apart like it did, there has to be a bad pulley somewhere in the belt path.
The A/C puts a good load on the belt - this extra load could very well cause the alternator pulley to act up to where you are hearing it.

I could also be way off base here.

Now that I am reading this thread again before I do the work this weekend, I want to mention that when I used to turn on the A/C, I would get a click noise and it would spring into action. Is this click noise normal. It seems like it would be.

I also understand that the A/C compressor pulley is also a clutched pulley. Is this correct? How do I check to see that this pulley is bad? Buy not using the A/C, what kind of load is this putting on the tensioner.

 

[dadsdiesel]

The click you are hearing when you turn on the A/C is the clutch pulley engaging.
The A/C compressor does have a clutch pulley, but works differently from the alternator pulley. The A/C pulley is totally free wheeling when the A/C is off. There is an electro magnet unit in the pulley, that when energized by turning on the A/C, it springs the clutch against the inside of the pulley thus engaging it.

So, when you are working on your alternator pulley with the engine off and the serp belt off, the A/C pulley should free wheel smoothly.

Also while you are in there, good idea to give the idler pulley a good spin and feel for any roughness.