Timing Belt Tensioners: Common Failure Causes

Hello.
'I had the timing belt replaced on my LT with the 5-cylinder, 2.5L engine a year ago. I ordered the tensioner pulleys as accessories. About 4 weeks ago, I had to replace the tensioner pulley for the front belt (crankshaft/water pump) with an original part because the accessory one broke. Now, both belts are loose again. The tensioner pulley for the water pump has a bent pin, and the tooth where the pulley is held on the front belt has broken off. There must be a reason why all of this is breaking. All the screws were also tightened to the correct torque. Has anyone else experienced this, or can anyone offer advice?'

Hi,
"Please search for the thread about the five-piece camshaft. The issue should be resolved with the original parts by now. With aftermarket parts, it's often hard to know for sure."

christians wrote:

With the original parts, that issue should be resolved by now

.
But he already has the original role, and yet he's facing the same problem again after such a short time.

For the rollers to break off, a considerable amount of force must be acting on them. I'm surprised that the belt has survived each time.

Either the belt is too tight, or there are dynamic loads occurring, for example, due to belts slipping on the pulleys. Have you noticed that?

Regards,
Guste.

I hadn't noticed that the original ones are already installed.

"QUOTES from the camshaft thread: Yes, the tensioner rollers on the five-cylinder engine are prone to breaking at that point. I've personally repaired approximately 28 engines (mostly T4s) because of this."
Hi Olli, don't worry too much about it; it mainly occurred with the ACV engine in the T4.
With my Audi AAT or AEL, I've only experienced that twice in 5 years.
In some T4 models, the tensioner bearing would sometimes fail at as low as 37,000 km, which is obviously alarming.
The affected tension rollers have been replaced, but they still have "Canada" printed on them.
The tension spring 074 109 243J was replaced with a new one, number 074 109 243R, in December 1998.
The new one has an "F" after the part number: so, 074 109 243F is at least a third variant.
Hello, don't worry too much, the tensioner pulleys have actually been changed (different material). To my knowledge, there hasn't been any engine damage yet due to the new tensioner pulleys.

What role are you playing now?
If this is the latest version, you should, as Guste already mentioned, check the surrounding area. Also, the defect on the pump belt pulley is quite unusual.

It's not possible for it to be too tight; there are arrows on the rollers to indicate the correct direction. Could it be that the pump is running too heavily, causing the tension rollers to fly off? Also, the roller is already the new version.

Hello.
I've found the culprit: the water pump is running roughly and intermittently, but only when it's installed. When it's removed, it spins freely. Don't be fooled if you encounter something like this.
Thank you very much for the other tips.