horrible engine noise. please help

[jamesn]

my truck (220k miles 22re 5 speed) started making a horrible noise yesterday. like marbles in a metal can being shaken. the noise fades away when you rev the engine up to 3k rpms. i had a leaking water pump so i replaced that. it was not causing the noise.

using my mechanics stethoscope, it sounds like its coming from the front of the valve train. it looks like the timing chain guides are still in place and the chain is not hitting the inside of the timing cover. i adjusted the valves. the noise is still there.

could it be the distributor?

any other ideas?

[Rickisan]

Man I would make sure the timing chain tensioner is doing its job. You probably already know if something happens there it can ruin the engine. I don't know how to do that externally though. Hopefully someone with more experience will comment.

[jamesn]

how can you tell if the tensioner is going bad or if it is out? i dont know.

[denniswoo]

if the engine has over 220k on it and with the history of chain wear on these things,and if the chain has never been replaced i think i would replace it.the kit comes with everything you need for about $80.you need to have a good strong light and look down past the top drivers side plastic guide the top section on my engine looked good until i got a really good look.