Hey guys. I know the 5.3's have a tendency to have that valve knock on cold startups, but how long should that last? It continues to knock on mine until I drive about 50 feet after I let it warm up for a minute or two, then it quits... It's only like 40 degrees here. Any ideas why it would be makin so much noise? Any way I can fix it?

 

It's actually piston slap, and they all do it (some worse than others). It's not worth worrying with. My old grocery getter could be mistaken for a Duramax first thing in the morning.....and it's 190K and still going strong.

 

Well I don't effin like it! lol, it scares me sometimes it gets so loud...you can actually feel it. It goes away, though, and won't do it for the rest of the day. Just in the morning times....

BTW, this isn't on topic, but I was actually considering gettin rid of my 5.3 short block and swapping in the 6.0. How hard is that to do? Can I take everything off my 5.3 and put it on the 6.0? If so, that'd be great. Let me know!

 

Yes, but I would do a 6.0 and buy a nice set of ported heads if your going that far!

 

Just so you know, my 06' 6.0L does the same thing on a cold morning with only 10k miles!

 

My 2000 6.0L makes all kinds of noise in the morning. Pistion slap on accel and valvetrain noise upon decel. I put 15W40 Rotella T oil in it last change and that quiets it down. The truck has 130K miles still running strong.

 

mine sounds like a old Powerstroke!!!! 155k miles and 5w-30 Mobil-1... Only on a 45 or colder morning... I let it warm up and stop knocking before i get in it or put it in gear.

 

i went with a little bit thinner oil this time around for winter, and mine knocks like the FBI on a crack house for about 1-2 minutes upon cold start up. its a lot quieter with some 15-40 oil in it.

 

 

I think im having the same problems with my 5.7 LS1. You can only really hear it when the hood is up. Its not a knock just a light tap and it queits down after warm up. I been freaking out cause i got a dyno pull friday morning.. So i shouldn worry,,?