knock at idle, annoyed!
09-14-2016, 08:27 PM
#1
knock at idle, annoyed! My 2000 sierra 6.0 has 187,550 miles on it. It's currently knocking at idle, warm and cold. If it sits for a week it doesn't do it. Under normal throttle it doesn't do it and seems to drive fine. It does need a water pump replaced. I don't understand if it's piston slap or a rod or main bearing, it goes away when driving though. I thought rod or main bearings you'd be able to hear even when revved up, or a vibration? Has a pulley ever been known to cause a knocking noise? The other thing I was thinking is maybe my tune? It's stock with a westers 89 octane tune, I don't understand how that could cause knick at idle and not under a load though.
I bought a 5.3 to go in but part of me thinks maybe the 6.0 is fine and it's something else not internal. No idea if people get piston slap when warm either.
I bought a 5.3 to go in but part of me thinks maybe the 6.0 is fine and it's something else not internal. No idea if people get piston slap when warm either.
09-22-2018, 04:19 PM
#5
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09-26-2018, 01:20 PM
#7
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09-30-2018, 03:11 PM
#10
We can all take shots in the dark here but until you post a good video showing the sound from multiple points in, around and underneath, no one here is going to be able to actually help you.
09-30-2018, 03:43 PM
#11
No not trolling just saying that TSB is complete BS............. real piston slap doesn't go away. GM is bullsheeting its buyers into accepting something else other than whats really going on. If you had loose slapping pistons the engine would be noisy all the time. Cold piston noise is normal in any engine, but its not slap or knock. If its knocking it something other than the pistons. Argue all you want, was just pointing out real piston slap doesn't go away.