timing chain rattle?

[Wozza]

just my take on genral engine noises
timing chain rattles all temps and go's quite as revs/load are put on,then makes a clatter as you come of the gas and it settles to idle....
lifters tend to tap whenever but are the worst at first start for the day....
balance bar tend rumble at idle and get drowned out as revs rise... they do tend to get worse as engine gets hotter buick more so than elmotech
harmonic balancer and rod knock sound similar and just get louder with rpm
little end, gudgeon pin, piston slap can ease with heat and load as parts expand and tighten up .......there is also flex plate rattle, water pump, alternator and power steering groans and bangs

 

[Immortality]

That's some great experience with engine parts failures.

 

[LatinDancer]

Firstly I'd like to say thankyou to everyone for their input to this problem....it's weighing heavily on my mind.
Previously I had not noticed this noise being present during idling, and had only noticed it there during acceleration uphill, but I just sat at some lights and noticed a slight tinkle at the same frequency as the noise. So I'm going to use a stethoscope to track down the bugger.

I did take off the serpentine belt and checked the water pump, pulleys and alternator...not them. So as it disappears with heat, it may be the little end & gudgeon pins.........groan ! Anyway.....time will tell, with a bit of help from a stethoscope.

 

[LatinDancer]

Wow....my noise sounded so much like pinging or a timing chain that I neglected to check the exhaust. But after banging on it in various places with a rubber mallet I find that there is a lot of rattling noise which is most likely the noise I was hearing.....which is why it disappeared when hot. But it's really hard to track down exactly where it is coming from.....there are heat shields everywhere. However there appear to be two small muffler-like thingies just downstream from the engine, which rattle more than elsewhere. Crikey, there are a lot of rattles....

 

[JamesSap]

just my take on genral engine noises
timing chain rattles all temps and go's quite as revs/load are put on,then makes a clatter as you come of the gas and it settles to idle....
lifters tend to tap whenever but are the worst at first start for the day....
balance bar tend rumble at idle and get drowned out as revs rise... they do tend to get worse as engine gets hotter buick more so than elmotech
harmonic balancer and rod knock sound similar and just get louder with rpm
little end, gudgeon pin, piston slap can ease with heat and load as parts expand and tighten up .......there is also flex plate rattle, water pump, alternator and power steering groans and bangs

Your diagnosis of the timing chain rattle is exactly what I'm experiencing, no sound as revs come up but as the motor comes back down to idle it taps/rattles towards the very end. temperature doesn't effect the noise either, does it regardless.

 

[Wozza]

Could also be balancer going or little ends,piston slap rattle
balancer easy to check run without belt, check rubber for cracks...chain or other maybe a stethoscope or screwdriver in the ear(pointy end at the motor ) to locate area of noise...