I have an 'o5 Cummins 5.9L engine that my son and I are rebuilding. I noticed the harmonic balancer has what appears to be an o-ring on one face (facing towards the crank) and what appears to be a dust seal on the other face (facing the radiator). What is the purpose of these two sealing surfaces? I cannot find a reason for them. Both look to be in pretty rough shape, so I thought I would remove and replace them only to find out that they are pretty deep, and I do not possess the skills, nor the tools to replace them. Are these "seals" necessary? I've seen aftermarket harmonic balancers that do not have these "seals" on them. If these "seals" are "messed up" thanks to my man-handling them, would I need to get a new harmonic balancer? Again, I'm not sure what the purpose of these "seals" are for. Can anyone help? Thanks in advance.
-Bill

 

Not replaceable need a new one! Not a seal part of the balancer. Its a rubber cushion for absorbing torsional loads from the engine. It goes from one side to the other!

 

Thanks D1965, you've always been a big help for me. I actually spoke to Cummins South Plains, and they told me that they stopped putting those dust seals in the Harmonic Balancer in '07, and there purpose was just that...dust seals that absorb torsional loads, but they found them to be unnecessary. They advised that I apply I apply sealant to the damaged areas and put the harmonic balancer back on the engine, and it would work fine. In your opinion, would you agree, or would you just purchase a new one? I've read on blogs that Cummins does not recommend the fluid-filled dampeners. What is your opinion on those types of harmonic balancers?

 

Yeah if it's not to bad that will work it's when it starts coming out that you have to worry. As far as liquid filled they work i run a 6.7 one on mine they are standard on the newer motors so seems to be a step in the right direction!