The noise is still apparent, comes and goes but mostly occurs when the engine is cold. Then, after several minutes, goes away.

Could this noise be caused by a failing oil pump?

 

Failing oil pump? Noise could never go away. Exhaust leak noise goes away after the engine heats up. Find the leak and repair.
Also check EOP to confirm.

 

valve train, lifter most likely

the LS engines have this issue after a few miles, the design of the engine causes the oil from the top end to poor down on top of the lifters causing dislodged debris to fall down on top of the lifters causing trash to get lodged in the lifter and causing the lifter internal piston to stick down in the lifter bore.

If you pull the coil pack and valve cover and take a close look at the rocker arms for a loose one, when you find the loose one take a close look at the rocker arm and the push rod, if all looks good then you can bet its the lifter. If you take a bore scope and stick down in the pushrod hole you'll be able to see the lifter plunger is down from the stop clip. The loose rocker arm is a dead giveaway as the lifters should have pre-loaded when the rocker arms are tight.

You can us a slightly longer push rod temporarily to take up the slack but I wouldn't leave it that way for any length of time as that will move the rocker tip off valve stim center slightly which over time can cause the valve guide to wear.

If its a lifter the noise is loader at cold start up then as the engine warms up and the internals start expanding it takes up the slack and the noise goes away until the engine cools again.

Do a google search for LS lifter noise,

Neal

 

This video is exactly what it sounds like.
What's the repair for this and price in your opinion? Would an engine flush fix it Thanks? Thanks!

 

there are a lot of videos showing how to use solvents to try and break down whatever is lodged in the lifter, sometimes it works and sometimes it doesn't.

I would start by removing the valve cover and positively identify the issue, if it is a lifter then move on but it could be as easy as a rocker arm failure without subsequent damage.

I'd start with engine flush and then depending on your abilities move on from there, ultimately a look in the engine would be the determining factor on where to go after the flush.

If the engine is clean with little to no buildup then pull the head and change the lifter, if there is a good bit of buildup then pull both heads and replace all lifters with a good inspection of all valve train parts, head rebuild and intake cleaning.

Top end rebuild price can vary depending on who does it and where in the US you live so you may have to check around for that.

Neal

 

Marvel Mystery Oil or SeaFoam will free/clean up lifters. Follow label instructions and run the vehicle for a few hundred miles then change the oil and filter with a good quality synthetic oil.

STP also make a good engine flush and it really cleans up the internals of an engine, BUT I have seen some threads where people start seeing leaks from the rear main a few months after the treatment on high mileage engines.

try the I would do the Marvel Mystery oil or Sea foam first and if it doesn't work consider stepping up the game with the STP treatment. If this doesn't work its time for some replacement lifters.

 

Get yourself a Mechanic's Stethoscope

 

Haven't had time to post but wanted to update.

Engine noise gone and solved! Oil pressure back to normal from a cold start. Solution? I did an engine flush using the Liquimoly product, amazing stuff.

After I ran the engine 15 minutes and removed the drain plug, nothing flowed out. Then a few seconds later, wham, a big glob of gunk came out and it drained.

I only use WIX filters and Mobil 1 synthetic oil, always have in all my cars. In spite of that though, there was enough gunk in the engine to clog lifters and other things.

I highly recommend the Liquimoly engine flush product

 

you have a video of what it sounds like now to compare to first post?

 

Something does not seem right, here.

If you always used synthetic oil like Mobil 1, REAL synthetic oil and not some weird Castrol blend, then you would NEVER get a slug of goo in the oil pan like that.
If you look inside any valve cover opening on an engine that has always ran, or even mostly ran, full synthetic, it looks like a new engine. Zero deposits, no carbon, no dark/black gunk of any kind.

Full synthetic does not ball up "gunk" I have been using Mobil 1 synthetic since 1993 in every car I have owned. Never any deposits.
Wondering if your "gunk" is some remains of a gasket material, paper towel, rag, insides of the oil filter or some other foreign item that got into your engine.
Or more likely some reaction of some prior additive that was added.

There is more to the story.
Did you add anything to the crankcase in the past? Like some "super lube" material, flushing agent, etc?

Unless the junk you just poured in caused the gunk ball itself?

On an engine running full synthetic, and changes at max 10-12K km, you NEVER have to flush the crankcase. The oil detergents do that for you. i.e. there is nothing to flush.
What is your drain interval?

There is more to the story.

Now, I have seen those slugs when I worked as a kid in a fast-lube joint. Coming out of peoples' cars that did not change their oil for 20,000 miles. We had to jam a screwdriver into the drain plug hole to get the lumps start draining. But that was dino oil that was abused.

Fake Mobil 1 synthetic? Where are you buying it|?
Mobil also sells dino oil. Are you using the silver bottle Mobil 1 5W-30 full synthetic as specified?

Something does not make sense. You seem to be doing everything right.
So I put my bet on some additive that you added in the past, which congealed and plugged up the engine. Just a guess.