Rattle at low rpm's

[opos04]

My duramax rattles at low med rpm's. I dosen't matter if it's cold or warm. Has anyone run across this trouble, and is there a cure. It sounds like a rod knocking. People look at me like i'm crazy. I love my truck, but i can't take much more.

Help! David

[twinturbo3150]

take it in if it's still under warranty

[opos04]

It is a 04 with 146,000 miles. If i knew what caused thie problem i can get it solved.
Thanks for the reply.

[skylor60]

does it sound like in the old days when you got bad gas and the valves rattled or if you had the timing advanced to far? if so that what mine sounds like don't remember having this before ulsf maybe my memory is bad though

[Hondarider552]

need some info on the truck please.
lets start with a tuner?

[skylor60]

Bone stock just synthetic in crankcase and trans

[anthony.jackson84]

My LBZ has a rattle at low rpm, durning acceleration. It sounds like its coming from the right side of the truck underneath the cab. (I know thats where its at I have checked into the problem already). That is generally just a loose heatshield that is vibrating due to the engine increasing in speed. Might want to check into that.

Other than bone stock, where does it sound like its coming from? Does it do it at idle, or like mine low RPM during Acceleration? If like mine, sit / stand carefully in the bed and give a good hard listen. Check the bolts underneath the truck and ensure everything is snug like it is supposed to be.

Hope this helps!

[robert987]

check the harmonic balancer sometimes the rubber breaks loose and makes a rattling sound very loud when idling let me now if it is

[TaylorM]

i had the same thing as soon as i put my 4" exhaust in...just at low rpm.......i figured the pipe was hitting the heatshield so i began whacking the heatshield and it seemed to fix it.

cheers,

TM

[TaylorM]

sorry.... that was in resonpe to anthony.jackson84's post

TM