Rattle in front of the engine

[m1dn]

Hey folks, trying to diagnose this weird rattle in front of the engine.
It’s not constant, comes and goes randomly.

Doesn’t sound like it’s inside the engine plus it’s the non-afm 6.2.
Only had time to film it this morning and do a quick check, will be doing deeper dive this weekend.

Has anyone had anything similar?
The video is not the best, but you can hear the periodic rattle at the end more clearly.

Also noticed tensioner seems to be moving/vibrating up n down, how tight it should be?

Going to check power steering and remove belt to make sure none of pulleys or tensioner cause that rattle

Rattle sound video:

 

[B-train]

Take off both belts and then run the motor. That will tell you if it's belt or engine related.
I have the same truck and had a similar sound I believe and it ended up being dry bearings in the tensioner and idler pulleys.

You can pull the dust shield off one side, wash them out with brake clean, blow dry with air, and repack with new grease. I found that to be rhe best solution compared to the cheap aftermarket stuff available now.

 

[Foggy]

As stated above, take off the main belt and run engine for very short time to
see if the noise changes.
Your AC belt is a "stretch to fit" belt" so you'd have to cut it off to remove it
If you plan on replacing it then that would eliminate the compressor as the noise..
But it should be obvious if ac comp is an issue

 

[OR VietVet]

Just in case, you can use this tool to remove and install the a/c belt:

Amazon.com

Typically the noises you hear out of tensioners and compressors are very constant, once they start. In that video, I did not hear much to closer to end of video and was not that long, but I would definitely take the belts off and listen to see if noise disappears.

 

[m1dn]

Thank you everyone!

Took both belts off, actually AC belt is easy to remove/install

Definitely quiet now from other pieces being noisy, but the knocking seems to persist.
Seemed to get louder/persistent once it warmed up in few seconds without water cooling running.

Does that sound like an exhaust leak?
Will run an exhaust leak test tomorrow, wonder if both sides are leaking now, weird.

Made 3 videos to try and get the sound, one from under the steering wheel:
-

-

-

Will share more tomorrow after doing quick leak test.
Looks like it might be time to replace both manifolds, gaskets and try to get all broken bolts out ( if there will be any )

 

[B-train]

The inside one makes is sound like a main bearing. It sounds like the main bearing noise that Ford had in 1979 with their 351.

The second one has a funny spot where you can see something flutter by the oil fill cap at the beginning. Maybe a sign of exhaust leak? Or the fan was running......

I'd say piston slap, but if it's already been driven for many miles, then maybe something different. But, piston slap on a cold-ish motor can sound similar.

 

[m1dn]

The inside one makes is sound like a main bearing. It sounds like the main bearing noise that Ford had in 1979 with their 351.

The second one has a funny spot where you can see something flutter by the oil fill cap at the beginning. Maybe a sign of exhaust leak? Or the fan was running......

I'd say piston slap, but if it's already been driven for many miles, then maybe something different. But, piston slap on a cold-ish motor can sound similar.

The piston slap on cold is there but it’s different yeah.
That was fan i think.

Welp, hopefully nothing too bad, will check the leak tomorrow and if not that, start taking the top apart i guess

 

[OR VietVet]

I don't think is exhaust leak at all and would just check the manifold bolts to be sure. Sounds internal. Lifter? Just a guess.

 

[m1dn]

I don't think is exhaust leak at all and would just check the manifold bolts to be sure. Sounds internal. Lifter? Just a guess.

How common are lifter collapses on non-afm ls engines?

 

[OR VietVet]

I have seen threads here on lifter problems with the 2000 to 2006 5.3 engines and they are not AFM engines.