T6 TDI, squealing ribbed belt, TPI

Hello,

The serpentine belt on the T6 occasionally squeals.
The belt has been replaced twice, as has the belt tensioner. The last tensioner I installed didn't really tension anything; it seemed to be stuck in one position.

Now, the new tensioner is also making a squeaking noise, and the tensioner wheel isn't quite centered on the belt (it wasn't like this when the tensioner was new; it's slightly offset).

I didn't notice any difficulties during the last changeover.

Does anyone know what changes are being made at TPI regarding this topic?

Best regards, Rainer.

Hi,
I don't know if there's a TPI related to that topic. There is no longer direct access for end customers.
Basically, I would check all the idler pulleys (and of course the tensioner pulley) for smooth operation. Is the stud on which the tensioner is mounted straight, properly tightened, and not overtightened? Are the screws on the idler pulleys also straight? Is the tensioner pulley original?
It looks like the roller is sticking, and the tensioner pulley doesn't seem to be the right size.
According to RLF guidelines, when replacing a belt, all the associated rollers should be replaced as well.
I've only heard those noises from a Passat with a fixed tensioner, as mentioned in the signature. When there was too much tension, the belt started to squeal, and once the tensioner pulley was stiff, causing a squeaking noise when the engine was cold.
hg
Herbert.

Good evening, Rainer,

You have a private message.


The TPI recommends "Litens" as the current manufacturer for the tensioner pulley and the use of lubricant (part number G052 172 M2).


Best regards,

Michael.

Hi Herbert,

Thank you for your thoughts! There is exactly one idler roller, but it was working perfectly like the rest during the last change. I couldn't detect any signs of it being a warehouse item.

The clamp doesn't sit on a fixed stud, but is attached with a screw to an aluminum base, where it lies flat, and a protrusion secures its position.

Yes, there is a TPI. Are you sure? I can find information about it online.

Best regards, Rainer.

Hi Rainer,
I only had access to TPIs through Erwin. If you know the "number" or identifier of the TPI, you might be able to find information about it online. For a specific model year, there might have been a TPI (Technical Publication Information) document specifying a shortened replacement interval for a particular component.
I'm not sure which engine series your motor belongs to (EA189 or ERA288)), but in my versions (Audi with EA189 and Golf with EA288, as shown below), the timing belt has two idler pulleys, also called tensioner pulleys.

hg
Herbert.

Hello Herbert,

I had blinders on, and you shouldn't quickly post something on your phone for just 1 minute before anything else while on vacation.

It's not the timing belt, but the ribbed belt. I have absolutely no idea what's going on, is it an autocorrect issue? It should have been proofread, regardless.
Sorry for the confusion .

The TPI number is: 2041442/1 for older engines, apparently not for mine.

Here (at home), I actually find information about TPI, but I don't have access to it on my phone while on vacation.

So, if the thing is squeaking, or if the serpentine belt is torn:
- There must be no belts anywhere that are wrapped around any axles.
- The LIMA free-range system must function.
- All drive belts/pulleys run smoothly with no play.
- The "improved" tensioning device is: V-ribbed belt tensioner 038.903.315.AN or AP.
Source:

The wrench is different from the one I have.

It seems that this only applies to older engines, but perhaps there is a newer TPI available.

Best regards, Rainer.https://www.bolidenforum.de/forum/{MARKER}

Hi.

Does the sound change when you spray silicone spray onto the belt on the drive side?

Good morning.

Rüdi wrote:

Hello. Does the sound change when you spray silicone spray on the belt on the drive side?

Probably, it changes when you pour water on it. However, what I don't like is that the belt doesn't run centered on the tensioner pulley, but rather protrudes slightly. Is that normal? I don't want to jump onto the sidewalk every time I see a T6.

Best regards, Rainer.

Hi,
The ribbed belt is driven by the vibration damper (KRR wheel on the crankshaft). If the ribbed belt runs on a roller over the edge, there is something wrong with the roller or its mounting position. Not being centered doesn't have to be a problem.
If there were any squeaking or whistling sounds, I would have checked:
- Function of the tensioning device (you already know this; if it gets stuck, the KRR will definitely squeak).
- Ensure all moving parts are free and easy to move (you've already checked this).
- the free running clutch (you probably already have one, as it also tends to cause rumbling with a belt drive);
- the vibration damper (when operating and making squealing noises, briefly spray the ribs of the wheel with silicone spray). In reality, these ribs only show signs of wear after a high mileage. However, you could then end up replacing the entire rear wheel assembly (KRR) every week, which is pointless. I experienced that issue with 350,000 kilometers on the odometer.
hg
Herbert.

Hello,

Thank you for your thoughts. I'm slowly starting to suspect that the grooves on the pulley (vibration damper) on the crankshaft are simply worn out.

I've ordered some serpentine belt spray for now; I'll tackle the mechanics when it gets a bit warmer.

Best regards, Rainer.

Hello,

The belt has now settled in quite well. The spray didn't help at all. Unfortunately, I had to drive about 2000 km with a lot of squeaking. Surprisingly, it doesn't seem to be very hard on the belt. It looked remarkably good when I took it apart, and I was actually worried that it might be falling apart.

Today, I removed the old belt and checked everything. No abnormalities detected, everything is running smoothly, the tensioner is working properly, and the pulley is also fine.

My current suspicion is that the drive sprocket on the crank shaft is worn out. Unfortunately, I don't have a new one on hand, so I reassembled everything today using a belt that's 5mm shorter, which will require the tensioner to apply more tension.

So, the length is 1550 mm instead of 1555 mm. It would be great if that thing would just shut up now.

Best regards, Rainer.

Does anyone else have similar problems? So far, everything is okay, but only a few hundred kilometers have been driven since then...

Hi!
Yes, that's me, with my work van, a T6.
He had a new timing belt installed a few years ago, and most likely a new water pump as well. From a VW authorized service center.
It has been like that ever since.
The current mileage is 110,000 km.

Depending on the weather and humidity, he's chirping quite a bit.
People have often approached me about it after hearing it.
If I drive distances of over 50 km with it, will the problem go away?

Yes, it doesn't bother me, and I also know that nothing will happen.
But a private individual would certainly bring the car back to the workshop because of that.


I've also had issues with the KRR system in my Golf.
Yes, there are problems with the power steering.
The belt shows wear on the inner side, specifically on the tooth flanks.
The power steering pump impeller was heavily worn.
Then I replaced it, using a Gates belt.
It also sometimes made a squeaking sound. Under load while steering.

Then I bought an original belt from VW at an exorbitant price.
It's made of a completely different material.
Since then, it's been okay.

When I compare the belts:
I would say his was simply made of rubber.
The VW timing belt had a kind of fibrous material on its inner side. So, they observed something like a fibrous tissue.

@Steffen: Are you saying that the quality of the material you obtained from VW is comparable to the quality of the material from Conti? There are some differences from manufacturer to manufacturer...

Gremlin wrote:

@Steffen: Are you saying that the :wink:quality

you obtained from VW is comparable to the one from Conti? There are some differences from manufacturer to manufacturer...
I've already tried several different manufacturers... but they always seem to break down after a short time.