Toyota Repair: Toyota carolla rattle noise at start up, drive belt tensioner, toyota carolla

Question
our 99 Toyota carolla automatic Trans.(70000 mls) has a short (approx. 3 sec) rattle noise at start up in the engine compartment that sounds like a loose chain.
Otherwise the car runs like a charm.
Q. could it be the timming chain, and does it need to be replaced immediately?

Answer
Timing chain problems are very unusual on this model, it may be the drive belt tensioner, toyota had issued a service bulletin for this noise, it recommends replacing the belt tensioner and the belt, see the toyota dealer for the updated parts.Refer to TSB EG015-01.