Hey guys, I got a 2006 Silverado 5.3 with 127k miles and yesterday I did an oil change, plugs and plug wires and I used Castrol 5w30 synthetic high mileage. Well at a cold start, and sometimes at a warm start when it’s been sitting a while has a quick knock to it (maybe a couple seconds) then goes away. It’s never done this before, does anybody know what this could be?

 

Bump.

 

It could possibly be piston slap.

 

I thought the same, but not sure if that problem extended to 2006. I had two pistons replaced in my 2000.

 

I ended up going back and tightening up the plugs and resetting the wires and changed the oil again with mobil1 synthetic and it really cleared a lot up, but it still makes a good bit of noise.

 

Could be a lifter beginning to collapse.

Pull the valve covers and spark plugs. Rotate the engine clockwise using a socket on the crank pulley bolt. As you see valves reaching max lift, pause for a moment and observe the rocker and spring - if the valve starts to close on its own, the lifter is collapsing.

 

They’re only noisy for about 2-3 seconds when the truck is cold or been sitting a while. Could it still be a collapsing litter?

 

Yes, I think Gumby22 has something, still doing it, worth a shot.