knock... knock, knock

[duramaxsandwich]

loud knock at idle, unnoticable at all when driving. anyone have an ideas on what it could be? its coming from the motor, i've heard many different people talk about it with their duramaxes and many different explanations. fuel rail pressure high, air pockets....?

thanks,

jake

[myojunk]

i've heard some people speak about injector knock. but i have never heard it that i know of...

[DuraBeast]

Sandwich,

There is another post on here, March 07. They talk about the "typewriter" knocking sound. Mine does it too. Concerned me. Here's what "fenmor" said from the post:

Originally Posted by fenmor

*** Bulletin number 02-06-01-022F (section 06 - engine /propulsion system) 11/30/2006 ***

It says in short................

This noise is caused by the relationship of the engine cylinder block, crankshaft journals, bearing inserts and the oil film. This relationship may allow a vibration that resonates through the cylinder block and is heard as a metallic ticking noise. The noise could be described as an irregular ticking or clacking sound, like random typing on a mechanical typewriter.
All Duramax diesel engines have this condition, however, some are more audible than others.
Testing and engine teardowns with this condition reveal no condition that would affect reliability or durability of this engine.
Dealers should not attempt to compare any customer vehicles exhibiting this noise with other similar vehicles as the noise is different form vehicle to vehicle.
This noise is a normal operating characteristic of the engine. This noise has no short or long term effects on the engine . Do not attempt repairs for this noise.

info numbers :

GMC 1-800-462-8782 USA
1-800-263-3777 Canada

Chev. 1-800-222-1020 USA

Link to the post: Engine Ticking Noise

[duramaxsandwich]

thanks, i've changed the fuel filter and switched additives and it has gone away for the most part.