2013 Tahoe 5.3 - engine noise help

[acesttz]

I need the great collective wisdom of this group. Any help is appreciated.

The truck: 2013 Tahoe 5.3, full AFM delete, Texas speed lifters and cam (stock grind) with VVT, high volume/pressure oil pump, BlackBear tuned. This set up has about 120K miles on it. Truck has 185K.

The truck has run flawlessly for 120K miles. Oil changed every 5,000 miles.

The problem: within the last 200 miles the truck started making a small noise that sounded similar to catalytic converters coming loose and rattling. Yesterday that turned into a much louder metallic nouns that increases with engine speed. It is NOT the collapsed lifter tick/tap. I have been through that an know what it sounds like. I have eliminated all pulleys, water pump and A/C as the cause.

Also, there are NO codes and oil pressure is steady - hot or cold - at 35-45 psi.

Any ideas? I am stumped.

 

[Geotrash]

A video would be a huge help. You can upload it to YouTube and link it back here. Just set its permissions to public.

Check the exhaust manifold heat shields. And, the cats can fail with a rattling noise when the matrix inside them breaks down. Also, a mechanic’s stethoscope from any auto parts store might help you narrow it down.

 

[mikeyss]

Why not post a video since you seem to have ruled out the common issues?

 

[iamdub]

+1 on video(es) and mechanic's stethoscope. You can bump on the cats with a rubber mallet to see if they rattle. Bring a bright flashlight, small screwdriver and 15mm wrench with you while you're under there to pry the inspection cover off and check the flexplate for cracks (particularly around the center) and the converter-to-flexplate bolts for tightness.

 

[swathdiver]

I need the great collective wisdom of this group. Any help is appreciated.

The truck: 2013 Tahoe 5.3, full AFM delete, Texas speed lifters and cam (stock grind) with VVT, high volume/pressure oil pump, BlackBear tuned. This set up has about 120K miles on it. Truck has 185K.

The truck has run flawlessly for 120K miles. Oil changed every 5,000 miles.

The problem: within the last 200 miles the truck started making a small noise that sounded similar to catalytic converters coming loose and rattling. Yesterday that turned into a much louder metallic nouns that increases with engine speed. It is NOT the collapsed lifter tick/tap. I have been through that an know what it sounds like. I have eliminated all pulleys, water pump and A/C as the cause.

Also, there are NO codes and oil pressure is steady - hot or cold - at 35-45 psi.

Any ideas? I am stumped.

So you did an AFM delete and used a stock grind cam with VVT? Which one was that?

 

[Geotrash]

+1 on video(es) and mechanic's stethoscope. You can bump on the cats with a rubber mallet to see if they rattle. Bring a bright flashlight, small screwdriver and 15mm wrench with you while you're under there to pry the inspection cover off and check the flexplate for cracks (particularly around the center) and the converter-to-flexplate bolts for tightness.

Forgot about the flex plate - good call. Hope the OP comes back - that's not a problem one wants to ride around with for long.

 

[acesttz]

Thanks for the input. I will upload a video as soon as i can.

 

[acesttz]

Videos on Youtube

https://youtu.be/FhYnHkxgtR8

https://youtu.be/KzHYybKrUm4

I also visually inspected the flex plate. I rotated the flex plate and could not see any cracks. Also, there is no movement in the flex plate indicating a failure.

Thank you for the help.

 

[Geotrash]

Videos on Youtube

https://youtu.be/FhYnHkxgtR8

https://youtu.be/KzHYybKrUm4

I also visually inspected the flex plate. I rotated the flex plate and could not see any cracks. Also, there is no movement in the flex plate indicating a failure.

Thank you for the help.

You have a lifter failing and is in the process of wiping the cam. Get that thing out of there before you have real damage to the engine.

Here's what mine sounded like along with a shot of what one of the lifters looked like when I got it out.

 

[acesttz]

Thank you for sharing that. I will get the heads pulled and see if I can salvage the cam and engine.