VW T4: 40,000km with loose timing belt

Hard to believe, but true!
My friend bought a T4 van a year ago.
In order to get it registered in Austria, several repairs were carried out at a workshop in Vienna.
She also had the timing belt replaced.
Since the vehicle had a significant backlog of repairs, I have been busy addressing those issues.
Now, the cosmetic issues came up, like a vibration noise coming from the engine compartment. Yes, I know, you're saying "dummy" .
I suspected the serpentine belt tensioner, but it turned out to be in good condition.
After that, remove the timing belt cover and Holla the forest fairy!!!
The timing belt was completely loose!!!
There was, without exaggeration, less than 0 volts of voltage.
So, I went to my friend who's a mechanic, and he immediately noticed the timing belt tensioner.
He said the screw was broken and that it was clearly the fault of the workshop where she had the timing belt replaced.
You often hear horror stories about the T4 timing belt.
But the fact that the engine even ran for 1 kilometer is a miracle.
That noise has been there from the beginning.
And we drove cheerfully across Swiss mountain passes and through half of Germany.

After the repair, I realized how quiet a 2.5 TDI engine can actually be.
He had experienced strong vibrations while the car was stationary, and it also felt unpleasant when shifting gears.
I attributed the vibrations during gear changes to the dual-mass flywheel.
I actually wanted to sue the shoddy repair shop, but my girlfriend was just relieved that we escaped without any engine damage.

And the moral of the story? Don't trust any amateur except yourself.

Congratulations on your engine's "birthday" .

Thank you .

Yes, that's correct .

Our employee has already driven the vehicle twice without tensioner spring pressure, because the spring in the tensioner roller broke each time!
Luckily, nothing happened in either case.

"Broken screw, sounds like it was overtightened? I've seen this happen at various workshops, but luckily (I'm saying this now) it was on the pump belt (specifically the threaded pin for the pulley) or the tensioner for the V-belt."
It's usually glued in with some kind of metal adhesive or silicone, and it actually holds... at least until I try to take it apart in my small garage, which is incredibly frustrating because I don't have any threaded inserts on hand.

"Lucky to have," they say.

Sure, here is the translation of the text from German to English:

"Hello"

"Yes, the forest fairy... I've never heard that before either."
But it's also always a struggle to get the belt on... it's very tight from the start.

Yes, that's correct. He obviously had enough tension that he couldn't jump over it.
But when I imagine the kinds of vibrations and oscillations that were acting on the timing belt...
While stationary, it vibrated strongly and irregularly, likely due to the camshaft and the fuel injection pump attached to it generating opposing vibrations.
And when I think about the forces acting on the camshaft, fuel injection pump, and timing belt.
How many timing belts have failed in these engines, even though they were properly tensioned?

The only problem I'm currently having is that, after the "good" timing belt replacement, it now uses 3 liters more oil.
I think he's going to have to check the valve timing again.