Vortec 3700 Engine Noise

[telemike]

I'm trying to figure what noise I am hearing out of my engine. I have replaced the serpentine belt, tensioner pulley and idler pulley. Parked and engine idling, I can only hear the noise of the fuel injectors by the intake manifold. Everything else sounds ok. However, when I start driving I can hear a noise coming near passenger side that sounds like either an exhaust leak or air coming into the engine. Sort of a chitter/chuffing noise. I thought maybe the water pump but it is quiet at idle. I can get in the H3 while parked and crack throttle but I cannot hear it, only when under load.

 

[Hunner]

It must be the squirrels, what are you feeding them?
Have you checked the connections to the air filter box/
Do you still have that huge plastic air manifold/muffler box covering the engine, if so try to reseat that.

 

[telemike]

Yes, still have stock air intake util I figure out how to make home made one. I can't figure out if noise is rotational or just air moving. Doesn't happen at idle.

 

[deserth3]

Take a close look at the heat shield on the exhaust pipe. It's up very close to the header. Could be broken or some offroad crap got up there and pushed it close enough to the exhasut pipe to vibrate.
A couple of years back following neo on Kane Creek, Some I had gotten up there and bent mine just enough to vibrate on the pipe during excelleration. Drove me nuts for awhile.
I was able to reproduce it by putting the truck in gear, Holding the break and giving it some gas.

 

[telemike]

Alvin @ PCMforless doesn't think it's a serious issue. Most likely something with exhaust manifold/heart shields

 

[4speedfunk]

Yeah...I got the heat-shield rattle on my 2008. Turn up the Monsoon and drown it out.

 

[mkmcgreg]

Just had the dealer call, they are replacing axle seal #3 for me, but mine has been making a rattle at cold start ups and they say its an internal piece in the cat that causes this. Goes away once warm and its covered under the 8/80,000 warranty maybe something else to look at

 

[autumn walker]

Mine had a similar issue - dealer recognized it on a test drive, but could never properly diagnose / fix it.

I fixed it by getting an H2.

 

[JGBB04]

Just going out on a limb here but it's not the air vents creaking is it? an exhaust leak would normaly go away when it warms up