Guys I need help figuring out this engine rattle

[Dustin Jackson]

Hey guys I think it has come time for my Tahoe for a AFM lifter delete. I think I am having a lifter failure but this sounds different from other videos I've seen. Someone said the pushrod might be out of place causing this sound?

What do you think?

 

[Doubeleive]

does not sound good to be honest, the 1st thing you want to do is take the belts off both serpentine and ac to rule a external source in or out.
you are safe to start it up with no belt for a few seconds
do that and report back

 

[FasterBass]

does not sound good to be honest,

Understatement of the year right here. Sounds more like a rod knock...how many miles on the motor?

 

[Dustin Jackson]

@Doubeleive Sound comes from under driver valve cover

@FasterBass About 179,000 miles

 

[Dustin Jackson]

@swathdiver Where can I find a L33 camshaft? I am using part number 12583623 and am not having much luck finding a good seller.

 

[swathdiver]

@swathdiver Where can I find a L33 camshaft? I am using part number 12583623 and am not having much luck finding a good seller.

WorldPartsDirect on Ebay has them as does GMPartsGiant after a quick look. Getting scarce it seems.

 

[Dustin Jackson]

@swathdiver Thank you for that, I am going to look into getting that cam. Can you take a look at this parts list from Texas Speed to make sure I have everything selected correctly? This will be a for a 08 5.3.

 

[rockola1971]

Wow that sounds bad. Id verify that aint a rod knocking! Pull the valve covers and verify you dont have a rocker arm worn out at its pivot too!

 

[iamdub]

Hey guys I think it has come time for my Tahoe for a AFM lifter delete. I think I am having a lifter failure but this sounds different from other videos I've seen. Someone said the pushrod might be out of place causing this sound?

What do you think?

That sounds worse than just a ticking (weak/collapsed) lifter. That sounds like it's bouncing around in there. Could be really messed up, turned, maybe busted lifter tray. Or, maybe the lifter is just collapsed and that's the push rod bouncing around. Have a misfire or rough idle? Any DTCs?

You'll have to at least pull the cover to find which cylinder and assess. To really know the extent, pull the head. Then you'll know if a standard AFM delete would fix everything or if the engine will need more work.

 

[Dustin Jackson]

That sounds worse than just a ticking (weak/collapsed) lifter. That sounds like it's bouncing around in there. Could be really messed up, turned, maybe busted lifter tray. Or, maybe the lifter is just collapsed and that's the push rod bouncing around. Have a misfire or rough idle? Any DTCs?

You'll have to at least pull the cover to find which cylinder and assess. To really know the extent, pull the head. Then you'll know if a standard AFM delete would fix everything or if the engine will need more work.

@iamdub I agree, doesn't sound like anything I've seen online but the sound is coming from the top end. I plan on pulling the heads off this weekend to find the answer here but I want to get the parts ordered as soon as possible. If I find the damage it outside my scope of ability to repair and I have to return the parts, so be it.

p0306 cylinder 6 misfire is the only code