2005 Silverado L33 Engine Noise

[RINGOz71]

I have a 2005 silverado 1500 with the L33 motor. I've had this knocking noise since 170k miles and now it seems at times like it's getting worse, and others it sounds like it's getting better. The truck now has 215k on it now.

Truck does not seem to have a loss in power. Oil pressure sits above 40psi at idle and around 50-60 normal driving. Oil level is checked every week and Is topped off whenever its below half on the stick. Tried switching to a thicker 10-30 Penzoil high millage with no change in noise. 

 

The weird thing is, is that it seems to go away at higher speeds. You can here it get faster with higher rpms in a parking lot, but if you pull onto a main road and go, It sounds normal. I'm stumped and have been told many things from different techs at my dealer. Some say manifold bolts, some say a cracked flywheel, piston slap, rod knock, valves, lifters, you name it. I'm stumped and ready to put a new motor in it. Any insight is very appreciated!

I took a video on it

 

Edited November 21, 2020 by RINGOz71

[CamGTP]

Can you get a video of you raising the rpm slowly to 1,500-2,000rpm and back down?

 

Just set the phone or whatever on the tire and do it.

 

It's hard to say what it is but to me it's sorta valve train related. Piston slap sounds different than this video.

Edited November 21, 2020 by CamGTP

[RINGOz71]

First video is a cold start after sitting at work all day

second video is after driving home with the temp around 200

 

Ignore the exhaust leak. That will be fixed today. For some reason the magnaflow catback doesn't  like the magnaflow cats. 

Edited November 24, 2020 by RINGOz71

[CamGTP]

I'm still going with valve train/camshaft related. It sounds like it's going half the speed of the crank.

 

Could be a worn cam bearing or even a roller on a lifter that keeps getting louder. These engines are somewhat known for eating the cam lobe off on some.

[cat eye 121]

I have a 2006 that sounds identical to these videos. Thought it was lifters. But sounds more like bottom. Can hear it good down by the front tire. Did OP find the problem?

[davester]

ringo hasn't logged onto the site in 4 years, so you aren't going to get a response from that user.

you might use a mechanics stethscope to better localize what & where the sound is coming from.

and idky you would think whatever fixed the o.p.'s issue would also fix it for you.