Engine knock or undercarriage rattle?

[CallHerCamil]

A little backstory on my Camaro. It's a 2010 Camaro LLT V6 with 145k on the clock. I bought it pre-owned with one owner & blew the engine at about 48k and lucked out and got it replaced at the end of the manufacturer's 5-year warranty powertrain at the end of 2014.

I was getting a bunch of misfires, and then in Sept 2021, I got a p0089 and a strong smell of fuel. I threw my hands in the air and ordered a bunch of parts, including fuel injectors, spark plugs, coils, o2 sensors (constant misfires), rear fuel pressor sensor (p0089) & valve cover gaskets (oil on spark plugs).

Fast forward to June 2023 & I start it up for the first time since Sept 2021 & I say, let me try and swap out the fuel pressure sensor. I do so & the car runs & I take it for a spin & got up to 90 on the highway. On the way home, I hear this chatter and go ruh, roh.

As part of my plan and hopes to get it back running, I bought oil & had it on hand. I got it started, got excited, took it on a drive & got this rattle on the way home. I went to drain the oil & only 2.5/6 quarts came out. That freaked me out & I'm hoping this isn't another blown engine.

I drained & filled & let it idle for 20 & the rattle persisted. Can anybody differentiate a knock vs. an undercarriage rattle before I try oil additives?

Below is a video.

http://https://youtube.com/shorts/lP-weDlP-nY?feature=share

[Dave-G]

I'm a little confused here. You're saying you installed a new engine, ran it for 7 years, then had issues and a strong smell of fuel, fired the parts canon at it and parked it. 2 years later you got it started, took it out and ran it on the highway at 90 miles an hour and now it's knocking? If I'm understanding it correctly, it sounds like you ran it hard on 2.5 quarts of fuel diluted engine oil, and that that sounds like a rod knock. I'm not there to see it in person, but you had the perfect scenario to cook an engine going on there.

[cawengr]

Sounds exactly like my daughters KIA that ended up being a rod knock.

[CallHerCamil]

Originally Posted by Dave-G

I'm a little confused here. You're saying you installed a new engine, ran it for 7 years, then had issues and a strong smell of fuel, fired the parts canon at it and parked it. 2 years later you got it started, took it out and ran it on the highway at 90 miles an hour and now it's knocking? If I'm understanding it correctly, it sounds like you ran it hard on 2.5 quarts of fuel diluted engine oil, and that that sounds like a rod knock. I'm not there to see it in person, but you had the perfect scenario to cook an engine going on there.

Yep, this pretty much sums it up.

Fingers crossed that its a exhaust related rattle ��

I came here to get multiple opinions in case anyone is experiencing a similar noise.

For more context, the sound only appears between 2500/3200 RPM and not during idle after the 3200 range, it goes away.

[Dave-G]

Originally Posted by CallHerCamil

Yep, this pretty much sums it up.

Fingers crossed that its a exhaust related rattle ��

I came here to get multiple opinions in case anyone is experiencing a similar noise.

For more context, the sound only appears between 2500/3200 RPM and not during idle after the 3200 range, it goes away.

I'm pretty sure that at this point, it's just bad news. Rod knocks often show up at lower RPM exactly like yours is displaying.

[1JEWLDSSRS]

Well if that is an under carriage rattle, your engine is running like crap and vibrating very badly!! But from MY past experiences, that sounds like bad news, rod knock for sure. I had an older Challenger that did that EXACT same noise when I had a wrist pin break. It would only do it above idle.

[Bigalamo]

Check all your bases. Look and see if your motor or trans mounts are shot.

[1JEWLDSSRS]

I just listened to it again, check your exhaust system and make sure none of it is loose and hitting against any of the under body bracing. Just maybe.