A-class 140 timing belt
 

Hi guys, new member, wife has a A-class and just had the tensioner changed but theres still a rattle, the garage have said its the timing belt and its a complete strip down to fix it which they say will be £1200, is the correct that they need to strip down the engine and replace all the head gaskets etc?
Seems a bit extreme.
Thanks

We have heard there is a way of changing the timing chain by seperating the old chain and attaching the ne chain to one end and then crank the engine round until you get all the way round then just reconnect the new chain to itself?
Is this true/possible??
Its a '52 model
thanks