Insight/help with this loud constant tapping/ticking/knocking

[Scott MI]

Hello all, new member first post. Signed up and have been searching, reading, and watching videos but I still don't know what to think about this. Car is currently sitting at a shop parking lot and they gave me a price for them to get to and open the valve cover but they can't say that's where the problem is or if they will have an answer to the problem. If they need to go further than it's gonna be more money to chase it down. All they know is CEL is pointing to #4.

Just looking for insight and suggestions, what direction the diagnosis should take, where to start or any prelim tests before start opening stuff up? I'm all over the place on what it could be and every video I see I think something else. Trying to limit expenses on just getting an answer only to find out I spent hundreds of dollars only to find out it's not repairable and have to buy an engine on top of what I'm out in labor. I'm sure if it's not found right away the labor could end up costing at least 1/2 of the price of a motor .

Rocker arm/bolt, spring, push rod, lifter, cam, hinge pin & piston damage, lower end bearing or rod are all the things that I've seen as possible problems to cause the noise. Anyone with insight, experience, or suggestions on what diagnostic route to go or how to narrow it down? I've thought about doing it myself as I've watching the LIM/lifter replacement video but if it's not something in the valve cover then I would be lost beyond that.

2004 Grand prix GTP 3800 series 3 L32 and I'm shifting through P,R,N,D is why the sound is changing.
Scott MI

[Scottydoggs]

kinda sounds like a rod knock to me.

made a new vid, but bring the rps to 2500 rpm's for a few seconds, then let the throttle go and let it drop to idle on its own.

if its a rod knock the sound it makes will tell us.

[Fivefingerdeathpunch]

That sounds like a rod knock to me, as in the motor is dead.

You could pull the oil dipstick and see if it sparkles in the light showing that the bearing is gone.

[FordMan77]

Sounds like a spun bearing to me as well. If the CEL is pointing to #4 I'd pull that plug and see if it's all intact. You do run premium 91+ fuel in it, right? Are you loosing coolant?

[02NavyBlue]

Either rod knock or there's not much left of piston #4 and its banging around in there.

[Scott MI]

Thanks for the previous help, went and acted on some of your suggestions. So I got the video of the raising rpms to 2500, also drained the oil, but couldn't get a good picture of the oil so also took a video of that too. Is that what I'm seeing in the oil when I stir it is the metal sparkling? Pretty much cut and dry evidence of spun bearing that I've got here?

[Scott MI]

and oil video since I can't have 2 videos in same post

[Fivefingerdeathpunch]

She's a gonner for sure, which sucks. Pretty healthy knock she's got going.

Soon it's going to lock up if you keep running it.

[bonerjamz03]

Same thing happened to my old grand am (lack of oil in my case). I think I drove it for about 300 miles or so before it finally gave out and died while driving it lol.

R.I.P.