I have a 2004 GMC Sierra with a 5.3 completely stock other than a muffler. recently starting knocking (not the same as the noise that a lot of the GM cars are getting.
I've changed all my rod bearings because i thought it could of been a rod, but that didn't fix anything lol waste of 6 hours. anyways i checked all of my push rods and they are all straight. I'm thinking it might be the lifters now. seems like that is the last thing it could be. if anyone knows how to change the lifters or know a link with a video or instructions for a 5.3 vortec let me know!

thanks guys

 

Have you tried running trans fluid in the oil for a couple hundred miles to see if the sound goes away?

Is it a cold or hot noise and all the time??

 

The knock doesn't stop even after the truck has warmed up and I've put fluid in it in the gas and in the oil. It's got me baffled

 

is it a fast tapping sound like a sewing machine or a slower knock?

 

it knocks with the rpms

 

That's not what he asked. It's kind of important to know WHAT kind on knocking is going on so you can properly diagnose what's wrong instead of doing what you are doing....shot gun solution. Throwing parts at the car "hoping" it'll fix that problem.

If you really think that you can replace just bearings and it'll fix a rod knock then you have a little learning to do.

 

I don't know how to explain the noise. It's a mid pitched sounding knock that does not go away even after the truck gets up to temp. There's no need to be a *** hole either dude. I'm no mechanic

 

the reason he is asking what the sound is, is so we can determine what the problem more than likely is. the sewing machine tick is more than likely the lifters from experience. and i'm sure plenty others will agree.

 

A top end sound will be twice as fast as a botom end sound.

 

Worst case, get a really long, thin, metal rod and hold one end to your ear and place the other end on different areas of the engine. Unless you have a mechanics stethoscope. That would be the best way to figure out where the noise is coming from.