PLEASE HELP!! I AM OUT OF OPTIONS!! PLEASE READ!

[DuvalMustangSS]

Hey everyone! I really need your help with this one. I have a 2004 Silverado SS with 110K on it. I am in love with this truck more than my own wife( don't tell her). Two days ago, I started hearing a mild knocking noise from the engine on the passenger side. It only happens when I hit the gas and not when it idles. Once it gets to 1500 rpm, it is a mild knocking/ticking. I am by no mans an automotive expert and by no mean an idiot. It first sounded like my belt was frayed or going bad. I popped the hood, belts are fine. I took it to my mechanic that I have used forever and trust and he took a brief look. His first thought was my exhaust pipe at the bend under the engine had a pin hole causing the noise. We checked in and that wasn't it. He kept it for a couple days an looked more into it WITHOUT OPENING THE ENGINE OR GOING TOO DEEP.

He called his "GM conncet" and he said there is a coating or spray on the crank shaft and rocker arms in the 2004 6.0L's and it can come off and get into the rocker arm bearings and the lifters and cuase them to go bad. He also told me isolated the fuel injectors and the noise is from the passenger side #1 and #3 valves. The horrible news is if we replace the vlaves and the rocker arms and crack shaft and lifters, there is no gaurentee the other valves could go bad and do the same thing. His advice is to swap the entire engine and guarentee it won't happen again. This would be approx. 20 hours of work and thousands of dollars I do not have right now.

MY QUESTION TO YOU:

1) Has this ever happened to anyone else?

2) Has anyone ever heard of this "coating" that is suppose to be on the engines to help with the higher racing rpms and performance?

3) If no, what is your best guess on the cause and solution?

I am going to open the top of the engine up this weekend and take a look, but I do not know what this would look like if this coating is gumming it up. At 110K miles, this it nuts to have to swap the engine ESPECIALLY when there has never been a miss fire, engine light, and the engine is not shaking. Only a mild knocking/loud ticking noise

PLEASE READ THIS AND HELP ME! I DO NOT KNOW WHAT TO DO!!

Thank you for any help you can give to someone that is down and out...

[JF-03-SS]

One thread will do, I'll leave this one here and the others will be deleted.

[GI.SS]

Iv never heard of this coating... Same thing happened to a buddy, broken valve spring. Pop the covers and take a look. Honestly it can be anything. You have came to the right place. Start will small stuff, any codes? Sure there are zero exhaust leaks? Is it a tapping or clunking sound? How's oil pressure look? Cut the oils filter open and see if there's anything out of the normal there?

[Cramer]

As above, never heard of this coating before. I would also cut the filter open and check it for any metallic debris.

What have you done to your truck? Does it have cats? If so it's common for them to plug up around that mileage, and that would or could be the cause. Also what octane of fuel are you running? Premium fuel only.

You can also pull the plugs, and check them, as well as bad plug wires, or a loose or broken plug.

These engines are known to have a piston slap issue, and that could be the coating that the guy was talking about that is put on at the factory on the skirts.

Give us a rundown of your mods if you have any, and I'm sure it's going to be easier and cheaper than you think.

Bad or lower octane fuel will cause knocking under acceleration, broken valve spring is more noticeable under acceleration, but can also hear at idle, plugs and wires can also be the cause but you would more then likely get a misfire code, Cats are a culprit of many noises and can come out of the blue leaving you scratching your head.

Let us know what is done to it and we'll be able to steer you a little better

[BlueAKSSS]

As above, never heard of this coating before. I would also cut the filter open and check it for any metallic debris.

What have you done to your truck? Does it have cats? If so it's common for them to plug up around that mileage, and that would or could be the cause. Also what octane of fuel are you running? Premium fuel only.

You can also pull the plugs, and check them, as well as bad plug wires, or a loose or broken plug.

These engines are known to have a piston slap issue, and that could be the coating that the guy was talking about that is put on at the factory on the skirts.

Give us a rundown of your mods if you have any, and I'm sure it's going to be easier and cheaper than you think.

Bad or lower octane fuel will cause knocking under acceleration, broken valve spring is more noticeable under acceleration, but can also hear at idle, plugs and wires can also be the cause but you would more then likely get a misfire code, Cats are a culprit of many noises and can come out of the blue leaving you scratching your head.

Let us know what is done to it and we'll be able to steer you a little better

X2

 

It could also be a lifter issue, such as one not pumping up/clogged or a collapsed lifter causing noise in the valve train. I've seen them make noise before if the truck has not had regular oil changes. Here's a video on what I am talking about. Not saying the fix the guy does in the video is what you need just an example of a possible noise you could be hearing.

[LSupNorth6.0]

This may be a shot in the dark, but does your truck see high rev ever? Maybe you bent a pushrod. Like the others said, pop that valve cover off and take a peek. There's not a ton to see under there but it's a start. I ALWAYS cut my cars off first thing so I've never experienced noise from them, but I agree those could be giving you some phantom noise. My motor on my stand right now has 100,000 and the cam had noticeable damage to a lobe and a lifter chipped up- it WAS bone stock. If you have stock mani's I could see a minor exhaust leak to cause this issue, even with aftermarket header systems. Sometimes the gaskets are just shapoopee. Which leads me back to cats, it may have enough flow to support at idle but any rpm backs it up and causes spark knock. Maybe try running it open manifold. You may not hear much of anything besides exhaust at that point though. As for that coating.. I really doubt it's effecting anything in your motor, and I certainly do not see any reason to pull the motor at this point, maybe the head if you cannot figure it out from pulling the valve cover. Rockers are known to be a weak link but I'd think if the bearings or keepers failed it would be much more noticeable. Than a mild knock/loud tick. There are alot of things to check. I would say your short block is probably fine. Without knowing more from you this is about all I can think of. I know spark plugs and wires were mentioned. I could see a cracked/broken plug possibly doing this. Maybe you could try to catch the noise in a video for us.

 

Hope you can get it fingered out with minimal damage to the motor and wallet!

[LSupNorth6.0]

Btw, my motor is an 04 LQ9 and my rockers didnt have any such coating, I haven't looked at my crankshaft so I can't attest to that, but you may want to get a second "GM connects" opinion. I think you cam to the right place and the fellows before me and I gave lots of places to start the search. You did say it would be getting torn into this weekend so hopefully you figured it out. Update us if you can

[Black04SSS]

Never heard of this coating deal. I have heard of the needle bearings falling out of rocker arms on earlier LS engines, but I think that was mostly on early Fbody and Vette 5.7s. Higher mileage LS engines often have very audible piston slap that is more pronounced when cold. A good inspection of the upper valve train is a great place to start to rule things out.