Strange sound, timing chain?

[Mercury]

Hello!

1999 Jeep 4.0 manual. It started making a weird sound a few days ago. Today I pulled the serpentine and started it so I record this sound. It seems like it's coming from the front, lower down, maybe around the harmonic balancer. My buddy thinks it's the timing chain, wanted to confirm it before I started ordering parts. Could I get some more input?

JeepSound.wav

drive.google.com

 

[superj]

You might have to do a temp t3ar down to see whats going on

 

[LivR65]

It’s a good call to take off the serpentine belt to isolate the sound. If the noise is still present, it's likely not an accessory like the alternator or power steering pump, which the belt drives. If the sound is coming from the area near the harmonic balancer, your buddy might be right about the timing chain. On a 4.0L, a worn timing chain can create a rattling or ticking sound, especially if it's loose or stretched.

Another possibility is that the harmonic balancer itself is failing, which can make a squeaking or grinding noise if the rubber insulator is deteriorating. Check for any wobbling of the balancer while the engine is running, as that could be a sign of wear.

Before ordering parts, you could try removing the timing chain cover to inspect the chain slack. If it’s excessively loose or if the harmonic balancer looks damaged, you’ll know for sure which part needs replacing.