Wobbly harmonic balancer on 4.0 - is that normal ?

[Explorer_PL]

Hi -

On our 07 4.0 with 125k miles, when you look down the accessory belt, you can see the harmonic balancer (crankshaft pulley) "dancing" around a visible amount when engine running.
Other owners of the v6's - is that normal or is it going bad ?

Thanks

 

[CDW6212R]

Check that out carefully, all factory balancers are two parts with a rubber layer between them. Typically when the rubber begins to let go, you won't notice it before it affects timing, performance, or a CEL light. Try to determine if the outer ring is rigid(won't move by hand at all), in the same plane as the inner ring, and if it looks to have spun at all. Look for damage to the rubber seam area, excess rubber hanging out etc.

 

[Explorer_PL]

Thanks Don

No CEL but it's running rough at times. i am thinking the crank sensor gets mixed signals.
Also, I have a new belt and it's making noise already.

 

[Mbrooks420]

Should be smooth running. If it wobbles I’d guess it’d be out of balance. Get it checked out ASAP as Don suggested.