Fragen und Anmerkungen zum Zahnriemenwechsel Passat PD | Posts 16+

BM wrote:

As can be clearly seen in Stefan's picture, the spanner is a replacement part that is commercially available. The manufacturer is NTN. As far as I can tell (based on what I've seen so far), this is the only manufacturer that is currently or has been used as original equipment. The quality is 100%. The price is likely up to 40% lower in the open market compared to that of the exploiter. EDIT ENDE

This tensioner is sold in stores under the INA brand. In this case, it's part of an INA timing belt kit. The tensioner pulley is made by NTN, and the idler pulley is made by INA. You can also clearly see the blank space on the tensioner where, under different circumstances, the so-called "original part" number would be stamped. These pulleys and tensioners are also included in timing belt kits from the brand Gates.

Hello fellow mechanics,

It's that time again: My old engine needs a new timing belt. I have a question about the studs for the tensioner and idler pulleys. The repair kit from SKF includes two studs (M8/M8 with expansion to M10). So far, so good. Is it advisable to replace these? During the last timing belt replacement, I felt that the tightening torque (20 Nm plus 90°) was close to the yield strength of the stud.
Unfortunately, I haven't fully recovered from my previous experiences with damaged spark plug thread holes on the 35i. I have a stud extractor from Hazet for that. Is there a risk that the aluminum thread in the head is corroded? Could the studs break off during removal (like they did with the exhaust manifold)?

If either of these scenarios occurs, it's likely to become extremely unpleasant. Drilling out a stud from the cylinder head is certainly not a simple task, especially if you happen to drill into a coolant channel. What do you think? Thanks!

However, the bolts that need to be replaced are actually screwed into the engine block, which is not made of aluminum. I have always replaced them during every timing belt change, and it has been completely problem-free. However, I also know people who haven't touched those parts even after 400,000 km...

matthiasTDI96 wrote:

Die zu wechselnden Bolzen sind aber doch im Motorblock verschraubt, der nicht aus Alu ist.

Hello everyone.

Unfortunately, that's not correct. The M10/M8 bolt is present in all 3/4-cylinder TDI engines, including the 16V models.
Cylinder head and therefore made of aluminum.
Only the pulley or the hydraulic tensioner is attached to the engine block.
I've already done several timing belt replacements and have never had any problems with the M10 threads in the aluminum.
That's why it was designed as an M10 thread starting with the first VP-TDI engines, because in the older D/TD models, it was still M8, and a helicoil kit was often used.
However, there are still some "so-called experts" who use thread locking compounds when installing fasteners, which often damages the threads when replacing the bolt.
Simply loosen two M8 nuts slightly and unscrew them, that's how I always install the new ones and tighten them just a little with my pinky finger.
There has never been a problem with that.

It's perfectly normal, and even intentional, for the bolt to exhibit some "elasticity" during the final 90 degrees of movement.

Regards,
Mpire

Hello,

The M10 bolts are not critical; they just need to be tightened all the way.
I always replace them; they usually come with the set anyway.
For this, there is also technical information from Continental, page 36, in the appendix.


The early 2.0 TDI engines are known to have issues.
I think there was an M8 bolt in there, and I've already stripped the threads.
We always converted them to M10/M8 threads in the workshop.

Sincerely,

Sebastian.

Hi!

"I've seen an M8 bolt break off in a workshop before. It happened 14 days after a timing belt replacement. That was great because VW has both a public and an internal repair manual."

And we targeted the general public with it.

After the internal inspection, the bolt would have needed to be replaced.

I also talked about it with my father beforehand because the Autodata repair manual also states that the bolt needs to be replaced.
But my father didn't do it.

Hello,

die Bolzen sind ohne Probleme raus gegangen. Das ging so leicht, dass der Hazet-Bolzenausdreher vollkommen überdimensioniert war. Allerdings sind die beiden Stehbolzen des Stoßfängers bzw. Querträgers abgerissen. Da diese allerdings keine tragende Funktion und nur zur Führung und Fixierung dienen, lasse ich diese einfach weg. Ich kann mir schon vorstellen, dass die Stehbolzen des Zahnriementriebs abreißen können. Das ist schon ein Bauteil mit Dauerbelastung. Wie Mpire schon richtig erwähnt hat, ist nur der Stehbolzen für die Umlenkrolle mit Schraubensicherung eingeschmiert. Der The tensioning roller does not have a screw lock because the securing mechanism is integrated into the aluminum component.

This time, I skipped the whole rigamarole of draining the coolant beforehand. Since some coolant always leaks out of the water pump anyway, you might as well let it all drain. To channel the liquid, I used a sheet of aluminum foil, which worked perfectly.

In a YouTube video, I saw that you can remove the radiator fan from the back (using an 8mm Allen wrench). This was much easier compared to the instructions in the manual (which involved fiddling with the four mounting screws on the fan itself).

Sebikom1 wrote:

Hello, The M10 bolts are not critical; they just need to be tightened all the way. I always replace them; they usually come with the set anyway. Sebastian

What kind of kit do you use? They never include them with Continental products.

chli1976 wrote:

Was verwendest du für einen Kit, beim Conti sind die nie dabei.

Hello,

This time, I bought the kit from SKF. It includes everything (rollers, water pump), along with the bolts and nuts.

Hello,

I usually use INA.

Regards,

Sebastian.

There has been a lot of discussion about this already (regarding manufacturers, component selection, etc.).

/viewtopic.php?t=25991&highlight=timing belt kit

A lot has been written about this. Hopefully, it will be helpful to someone.

Hello fellow mechanics,

nichts ist einfach... Der neue Zahnriemen ist drin (ging ohne Probleme rein) und bei dieser Gelegenheit wollte ich noch den Freilauf des Generators austauschen... von wegen. Da bei mir zum Gegenhalten leider ein T50-Torx erforderlich ist, habe ich einen von der Firma KSTools (1/2" Antrieb) bei Amazon gekauft. Bewaffnet mit einem 3/4-Zoll Montierhebel, einem Adapter auf 1/2-Zoll und dem körperlich stärksten Nachbarn haben wir versucht, den Freilauf abzuschrauben. AUnfortunately, nothing moved except for a twisted KSTools Torx screw.

Gut dachte ich mir, dann baue ich eben den Generator aus. Blöd war dabei leider, dass ich schon das Lüfterrad mit der 8er Inbusschraube und Schraubensicherung montiert hatte.

The lower screw of the generator can only be removed if the entire fan wheel (including the bearing and pulley) is reinstalled. Okay, so I put the old belt back on to prevent the fan wheel from spinning: that didn't work.
"Then I asked my wife to help me increase the tension of the belt using a lever: No luck, the fan wheel just spins freely. The fan wheel is mounted on a toothed aluminum body. To remove the lower generator screw, I simply broke off two teeth of the toothed aluminum body, and then it came out. Tomorrow, I'm taking the generator to a workshop to have them remove the freewheel using an impact wrench."

The question is now whether I can leave the fan blade with the aluminum housing and the two missing teeth as it is. Will a slight imbalance in the fan blade cause problems with the bearings?

One option would be to remove the fan with the viscous coupling by holding it in place against the pulley (using a pipe wrench) and then replacing it with a new one. What do you think?

Quote:

Die Frage ist nun, ob ich das Lüfterrad mit dem Alukörper und zwei fehlenden Zähnen so drin lassen kann? Führt eine leichte Unwucht des Lüfterrads zu Problemen mit den Lagern?

It's difficult to answer without knowing the specific part or seeing a picture. Of course, you could try to "balance" it by removing two teeth on the opposite side as well, but that's not ideal.

It seems there's a so-called "forehead hole wrench" used to hold things in place.
http://tool-is.com/print/html/product/69057/32194da54073b5ee88426c093221b2c3e819a6d3/1

Hello!
The last picture looks like a universal socket wrench; I have something similar for my old angle grinder.

And once again, regarding the viscous coupling:

It's been a while, but I think I remember that there's a small, inconspicuous flat surface somewhere on it for holding it in place. It's probably 32mm, 34mm, or 36mm.

I built a tool for working with viscous couplings because the standard open-end wrenches are too bulky. It's simply made by cutting and shaping a piece of 3mm sheet metal.

Isn't there an internal spline on the shaft to provide resistance?
hg
Herbert.

Edit: Wave = generator wave. Can you not feel these waves due to the fan blades?