From 150k miles and on the timing chain can stretch, and this causes the rattle, mainly from a cold start up but should go when the oil pressure has built up, after a few seconds. This is how they start off, it is seldom the tensioner that fails.
Is there any difference between a cold start up and after it has been running sound.
The Idler gear on the front for the belt causes more rattles than the chain.The info for cars is much easier than for the Vito due to the variations in the amount of Vito's, often the alternator has to be removed to get to the tensioner.
i got the alternater off and got the tensioner out it is fully out so im guessing it needs a new one. i think the rubber plasticy shoe need changing aswell does the engine need to be stripped for this?