[89 5.0 LX]

This morning I got in my car and started it to go to class... and I immediately noticed a vibration... one that was never there before.

It this vibration occurs at idle and up to about 1500 RPM, then it goes away. It vibrates with the clutch pressed down and also with the clutch out.

I took the serpentine belt off to eliminate the accessories, then started it and it still vibrated the same. It has brand new motor mounts from Ford, so that is not it. It starts and runs fine like it always has, and there is no loss of power.. (not misfiring)

As for the harmonic balancer, you can see the rubber in between the inner part and the outer ring, and you can't really move it either.

[dr.gonzo]

How new are the mounts?

and have you looked under the car?

[89 5.0 LX]

Engine mounts are brand new... and the vibration occurs when the car is stationary. The mattress/driveshaft isn't rotating when the car is stopped.

[dr.gonzo]

Maybe the old ones were so loose, you never noticed the shimmy and now the new ones are so tight you feel everything.

Like airing up the the tires to a higher psi = a more bumpy ride.

I don't know, any time something happens to my car I look at what was done to it last.

[93hatch]

balancer fosho

[89 5.0 LX]

Originally Posted by dr.gonzo Maybe the old ones were so loose, you never noticed the shimmy and now the new ones are so tight you feel everything. Like airing up the the tires to a higher psi = a more bumpy ride. I don't know, any time something happens to my car I look at what was done to it last.

I know what you mean about checking what I did last. But I haven't done anything to the engine lately. I know its nothing to do with the tires or the driveshaft or any of that because it vibrates even when the car is stopped.

I put the new motor mounts in about 20k miles ago. It has never had this vibration probem before, ever.. until Tuesday morning when I first started it up in the driveway. I noticed it as soon as it fired up, parked in the driveway.

It is seeming more and more like the balancer all the time. It is definately a rotating mass vibration... it is shaking the hood, the doors, the seats, the dash, and the steering column. Even the spare tire in the trunk is rattling.

I can't turn the balancer at all but I can pull/push on it and move it front to back just a little. I guess all it takes is for the outer ring to rotate just a little to throw it out of balance.

[89 5.0 LX]

Got it home (put it on a trailer, 200 mile trip) and bought a new balancer. The old one didn't really move when I tried to twist it, and the rubber still looked fine, but when I compared it to the new one, the outer ring on the old one had turned about 180 degrees from how it should be.

I cleaned the crank with a scotch brite scuff pad and put a little grease on it, and the new balancer slid right on. I put a welding glove on and hit the balancer a few times with the palm of my hand, and it went on all the way.

Now it runs perfectly smooth!