Loud slow knocking noise diagnosis

[FxFormat]

2015 LX570, 213K miles


Just heard it this morning, i just recently drove the truck 3000 miles on a road trip, everything was normal but this morning i woke up and engine sounded like this. Oil level is full, 5w30 has always been used, oil pressure is good. This noise is slow and does get faster with RPM changes but i can't seem to hear it above 2K RPM. Truck drives like new otherwise and there are no codes. Any help would be appreciated!

 

[dudemancool1904]

Is it louder in the front or the top of the engine? Does it go away and come back?

 

[jfz80]

What’s the condition of the serpentine belt?

Seems too slow a rhythm but had a bad belt make a similar noise that I assumed was the doom of a 1fz. Turned out to be a crack in belt going over tightens radius pulley.

 

[GrouchyTech]

Check your belt tensioner. It will be moving back and forth A LOT. Replace it.

 

[FxFormat]

It sounds like it’s coming from the vvti solenoids, I’ll swap them with my tundra on my next day off and see. I dont think a serpentine belt or tensioner would make such a loud metallic tapping noise.

 

[GrouchyTech]

It sounds like it’s coming from the vvti solenoids, I’ll swap them with my tundra on my next day off and see. I dont think a serpentine belt or tensioner would make such a loud metallic tapping noise.

A broken tensioner will sound just like this, give it a visual check while it’s running. It’ll make this noise as the tensioner spring loads and then releases.

A five dollar mechanic stethoscope has the potential to save a lot of time and money.

EDIT: Sound familiar?

 

[99toylc]

I agree with others - check the serpentine belt for faults

 

[99toylc]

and all the pulleys / tensioner

 

[FxFormat]

A broken tensioner will sound just like this, give it a visual check while it’s running. It’ll make this noise as the tensioner spring loads and then releases.

A five dollar mechanic stethoscope has the potential to save a lot of time and money.

EDIT: Sound familiar?

Oh man, that's exactly what mine is doing. Thanks for that! I'm off tomorrow i'll be able to tackle this, visual inspection of the tensioner didn't reveal anything, but i'll remove the belt tomorrow and start the truck and see if the noise goes away then it's the issue.

 

[FxFormat]

Check your belt tensioner. It will be moving back and forth A LOT. Replace it.

Many thanks brother, your diagnosis was correct. I couldn't really see the tensioner with all the covers on this truck, took everything out and looked at it from underneath and saw the tensioner clicking every belt rotation. Replaced it with a new OEM unit and all is well, she purrs like new and runs so good.