300tdi timing belt help

Does anyone have any ideas what may have caused this, i found it after the belt snapped which was replaced around 2 years 15k miles -

Belt ran out of true ? Tension or idler pully bearing fail ? Crank pully came loose ? Have you found out yet what other damage you have

robbiemcvee said:

Does anyone have any ideas what may have caused this, i found it after the belt snapped which was replaced around 2 years 15k miles -

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I would suggest something hasn’t been aligned or seated properly and the belt has wondered.

Belt misalignment or one of the pulleys (unlikely to be one of the cogs) to be misaligned causing the belt to walk off center. That will also be the reason it snapped if it was wearing against the casing.

Thanks for the replies, had a couple of push rods bent and one of the rockers has snapped, so ive replaced all the push rods and the broken rocker. Bought a full kit of seals and pulleys, ive aligned all the markers and the keys, but i think ive seen somewhere where there are 2 lines on the flywheel that give the correct alignment for the flywheel - but i cant for the life of me find the youtube video or any reference to these markers on the 300tdi?

forgot to mention there was no o ring on the crank, the picture is where the belt snapped

Watch this chaps vid on LubeTube, steps you through a 300tdi belt change and setup.

slomofo said:

Watch this chaps vid on LubeTube, steps you through a 300tdi belt change and setup.

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thanks for that

Although your belt has been rubbing on the cover, there does not seem to be much wear on the belt and probably not the reason it failed.
If it was rubbing badly, the front edge would be uneven and the timing cover would be full of black fluff from the belt.
Was the belt tensioned properly with a flex type torque wrench?

it was fitted by a local specialist, your right though there is no evidence of it rubbing

Are there any clues at the ends where it has snapped?
At least timing belt failure on a TDi isn't as catastrophic as most modern engines.

it snapped badly

What make is/was the belt ? ( Curious ).

robbiemcvee said:

orgot to mention there was no o ring on the crank

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IME, that tend to lead to oil entry into the timing case - but your timing case doesn't look too bad ...

Rougharse Racing said:

Was the belt tensioned properly

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+1 - Doesn't seem to be much else that can have caused that, based on what we know so far ....

its a dayco belt, i think i'll just put this back together and hope it doesnt happen again

robbiemcvee said:

it's a dayco belt

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- Dayco might be interested in that, maybe... certainly worth contacting them IMHO ...

If you're going it DIY ( which I'd strongly advise ), then the vid posted above in post #7 is a fine method

Mike on Britannica restoration showed the cause of over tightening a timing belt. It puts wear on the Injection pump pulley. This make the belt ride forward and snap, cause the wear you have on the cover.

It looks like something has suddenly stopped and the belt didn't.

Al2O3 said:

It looks like something has suddenly stopped and the belt didn't.

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Yup, looks like it.
As said, it was rubbing on the case but that didn't cause the failure.
There have been instances where the belt was found to have been worn down to half its width and held till it was found in the nick of time.