2000 5.3 knock, help diagnosing cause?

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I have a loud knock at cold start up, or after sitting 6-8 hours on cold days.
the truck has over 180k miles.
The sound goes away within a few minutes. It sounds more like a knock than a lifter tick, and seems to deep of a sound for piston slap.
I am running 10w-30 Valvoline synthetic High mileage. here is a video of my truck the other morning.
thanks for any help

https://www.youtube.com/watch?v=nI0T4RsyoAw
 
There are alot of threads on here and other forums..i have read about half of them. The consensus is pretty much replace all the lifters or just get used to it.. no ill effects other than just aggravating you to death.


There are also youtube videos of 'fixes' with MMO or ATF or Seafoam etc etc etc..
 
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I thought that problem was limited to the 5.3 w/AFM. Guess not, thats the noise.. a lifter gouging a cam lobe.. Gotta fix it, can't live with.

Is there a check engine light on?
 
I can see your pressure gage went up to just over 40 psi when you started the engine, which is good. I agree that is stronger than normal GM piston slap. Wondering if one of the lifters is bad.
 
But.. all GM engines have a bit of piston slap cold.. mine did that a little. Got the right oil and filter and its just about gone.

What oil brand and weight and what filter are you using?
 
Originally Posted By: LeakySeals
I thought that problem was limited to the 5.3 w/AFM. Guess not, thats the noise.. a lifter gouging a cam lobe.. Gotta fix it, can't live with.

Is there a check engine light on?

The check engine light comes on if I keep it above 2000 RPMs for very long so if I go down the highway and I go over 70 I will get a flashing check engine then it stays solid if it's very cold out and I'm going 35 or 40 I will also get a check engine if the RPMs go above 2000 for more than a few seconds the code is p0300 random multiple misfire.
I just put new iridium ac Delco in and it did not help
 
I am using Valvoline 10 30 weight high-mileage synthetic.
I just changed the filter the other day to a super tech cheap filter before that I had the AC Delco ecore filter in it the larger of the two
Have only put a couple of thousand miles on this truck since I bought it I was planning on doing frequent oil changes to see if that clears up the problem but it sounds a little louder than a lifter I thought
 
Hmmm well, it could be piston slap as these engines(especially the larger 6.0/6.2L) were known for piston slap, usually earlier on than 180K miles.
But from the video, it also sounds to my ears like a bearing under the hood that goes away...IDK, alternator bearing and belt???
 
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I had drain back with Super Tech filters from day one -- went with a Fram Ultra and fixed it on my neighbors Ram. Those 5.3L motors are known for your noise -- I would still get that filter off moving forward.
 
Originally Posted By: Snagglefoot
It's worth trying 5-30 oil and a Fram Ultra. What was the temperature the morning you started it? I heard it was a bit cold in your part of the woods lately.


I stopped using the Ultra on my 6.0 because piston slap got worse. I tried a better flowing lower efficiency filter and that helped a lot.
 
Originally Posted By: Snagglefoot
It's worth trying 5-30 oil and a Fram Ultra. What was the temperature the morning you started it? I heard it was a bit cold in your part of the woods lately.


In the 20s I believe. 26 maybe?
I may change my oil again this weekend. It's a shame to dump oil under 3k miles. And I just bought 2.5 gallons of delo 10w30. But I can buy some 5w30 if it may help.
Maybe a napa gold filter?
 
Forgot to mention.. If you have room try a pint or even a quart of Marvel Mystery oil. Used it for years to diagnose a flow or clog issue.
 
I thought the same thing, super tech is not a very small mesh. It's rated to 30 microns. I figured it would flow. Worst case my bypass would open. And I do have over 40 psi. As the oil warms up my pressure also increases.
 
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Originally Posted By: LeakySeals
Originally Posted By: Snagglefoot
It's worth trying 5-30 oil and a Fram Ultra. What was the temperature the morning you started it? I heard it was a bit cold in your part of the woods lately.


I stopped using the Ultra on my 6.0 because piston slap got worse. I tried a better flowing lower efficiency filter and that helped a lot.


Interesting. Wondering, did you changed the type or weight of oil at the same time. IE: changing two parameters in stead of one? Also, can you tell us which filter gave you the better results? Thanks.
 
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I did add a quart or Marvel's it did not help yet. I'm hoping it's just a small clog, and will soon flow better .
But as others have said it may be piston slap and nothing will cure it.
 
Originally Posted By: Mc357
I did add a quart or Marvel's it did not help yet. I'm hoping it's just a small clog, and will soon flow better .
But as others have said it may be piston slap and nothing will cure it.


I wouldn't chalk it up to piston slap. When you bought the truck it was quieter, correct? I'm guessing the problem showed up with the colder weather. Would that be right?
 
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