knocking noise

[TomTom]

I have a knocking noise coming from what I think is the right side of the engine. It is a light knocking sound I can hear at idle and up to about 20 mph, then wind noise gets to loud. I can't hear with the windows down either, even at idle. The think that completely baffles me is it has no rhythm. The sound does not speed up or slow down according to engine speed. The sound is also slowly be

coming a little louder.

 

Oh, the vehicle in question is a 2004 Suburban Z71 with about 10,000 miles on it. Any ideas?

 

Thanks

[GM-Tech]

If it doesn't follow engine speed in some way, then I don't see how it could be engine related. Can't say I can think of anything else that would make a knocking noise.

 

Had some problems in the past with the purge solenoid making a muted knocking type noise, but that was definitely rhythmic, though it didn't follow engine speed, and you probably wouldn't hear it off idle.