300tdi timing belt help

If there is no wear on the belt that snapped then, presumably, the worn groove in the timing case and seal in the OP's original picture was from a previous belt.
After setting the new belt up and doing the usual turn manually to check everything is ok, I'd then give it some good turning over on the starter, with the stop solenoid disconnected, as an extra and more vigorous test.

Al2O3 said:

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

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+1 - I'd had the same thought - which is sorta why I suggested asking Dayco - always presuming they have a technical dept. who will speak to "us" mere mortals

@robbiemcvee Just a thought, are all of your valve stem caps still there?

its all back together now, the cause of the brake in the belt is still unknown.. ill keep you posted, thanks everyone

robbiemcvee said:

its all back together now, the cause of the brake in the belt is still unknown.. ill keep you posted, thanks everyone

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Have you started it yet?

yes its started and running well - so far..!

robbiemcvee said:

yes its started and running well - so far..!

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Tremendous. Well done

300 recall years ago for mods as cambelt walking off pulleys, small mod was crank pulley had side lips, big mod was car needed whole new timing chest, if mod done was meant to be marked on chest with yellow paint
Iirc it was the injector pump mount faces to timing chest that was causing the issue, and the injector pump rear support bracket.

This is why every service you have a look at the timing chest wading hole, any dust means trouble is brewing!

Google, STC4095K, STC4096K, STC5095L and STC4096L