I'm getting a vibration past 50mph or so which stops at 70mph.

This vibration came at the same time that I was getting a type of squeeling sound coming from the pulley area. I noticed the the main pulley had a "shake" to it while the car was running and my mechanic said my harmonic balancer is bad.

Can I replace this part myself? Is the harmonic balancer the source of my high speed vibration?

 

if the harmonic balancer is bad you'll need a puller and I'd make sure the speed specific vibration is not tire balance related

 

If your pulley looks like its shaking or vibrating and all 5 bolts are tight (4 pulley and the big crank bolt) then yea your balancer is probably gone. It isn't hard at all. Just get a harmonic balancer puller, it looks like a birds foot, 3 slots on one end and one on the other. Even a steering wheel puller will work if it has the right threaded bolts.

 

can I do this without unbolting the motor?

 

Yes, at most all you'll need to remove is the fan and radiator so you have room to work.

 

changing out the balancer isn't that bad. You might want to stay away from the cheap balancers, i heard there no good. I got a Ford balancer for $80 shipped.

 

a stock balancer and/or a stock replacement balancer will have a rubber ring going around the entire circumference of the back side. a quick verification of whether its good or not would be to look at this ring. if it's sticking out more than 1/8" or is cracked/missing pieces in any spot, it has slipped and it no good anymore.

but, since your vibration is speed related, i wouldn't even bother checking it. when a harmonic balancer goes, the vibration will increase/reduce with engine speed.

 

when im looking down at mine, it looks like it has a wobble to it, but i feel no vibration.

would it be a good idea to go ahead and replace it, or just wait for it to "go" ?

would be nice to set my timing to an aftermarket balancer instead of the white out mark's on my stock one, lol.

 

A balance issue should not be speed dependant, it should be RPM dependant. Meaning what ever rpm you have the vibration at 50mph you should have the same vibration whenever the engine hits that same rpm and would usualy get worse as rpm increases.

I recommend you start looking at the driveline and tires.

 

looks like were the only two on the same page here