Rattling sound

[RickOTR]

I've had a faint rattling sound under my truck for a while now that I cannot solve. It sounds like a baby rattle by the balancer, but I cannot be 100% sure that's what it is. Could it be the 4x4 balance shaft chain riding against that tensioner.

 

[Saik]

I have that too on my Explorer, my mechanic said it could be the timing chain. It only happens during a cold startup, but goes away after a few minutes on idle, or when driving.

 

[BigRondo]

Rick, I had a rattling under my truck awhile back and it turned out to be a loose heat shield in the back by the spare tire carrier.

 

[RickOTR]

Rondo, it's right around the Harmonic Balancer. I did the timing chains and lash adjusters again not to long ago so I know it's not that either. The sound is so faint that you can barely here it. Engine runs great otherwise.

 

[gmanpaint]

Water pump?

I have had them sound like a rattle can in the past. Right before they broke!