I have changed every suspension part on my 97 SC2 as of last month except tie rods / ends and CV joints. All bearings original. Changed upper motor mount and vibes reduced greatly.

RK,

Do the #2 pencil test on your top motor mount.
If you can fit a pencil between the top metal piece and the top of the rubber, the mount is shot.

You don't realize it has worn out because the process is so slow. Usually get about 70K out of one. Replace with OEM AC DELCO upper torque axis mount.
OEM. OEM. OEM. Go cheap, get what you paid for......

 

Well, I still have the vibration going on after replacing the motor mount. Happens at 63, worst at 70 mph, remains constant.

Was at the tire/alignment shop getting my wife's Escape tires rotated (for free when you purchase tires from them, so I save my back and get free advice tidbits.

Crossed paths with s self proclaimed GM Master Tech and described the symptoms. I described what few things were left that had NOT been replaced. His response was that back when he was a tech w GM, he said Saturns frequently developed these vibrations, as they aged.

Root cause? Something in the drivetrain, not the suspension.
Hmmmm. Kinda might make sense, actually. If my new motor mount killed the vibration by 90%, WHAT was vibrating?

Possible Answer: Something attached/coupled to the engine that is rotating with the half axles (and therefore rpm are irrelevant). Working backwards

CV Joint
Half axle(s)
Worn Carrier bearing (allowing wobbling)
intermediate axle
Worn Transmission output shaft bearing / seal (allowing wobbling)

Time to learn!

 

That's very interesting to be sure. I talked with my tire guy and he had no clue. It's not much of a bother in the part of PA where I live, because it's only under load when I experienced that. Going to WV is when it was bad because it's so hilly down thataway.
Ron K

 

I have put a lot of miles on cars, Some front wheel drive, others rear wheel drive. All or four wheel drive I have not owned.
Vibrations have by in large been tires or out of balanced drive shafts in rear wheel drive cars.
I really have not had vibrations on front wheel drive cars. I have had CV joints go and they by in large have made noise on turning. My Saturn does not have any vibrations.
Reading through this I get the impression this has around 250 k on the clock.
You say the vibration is worse pulling a hill.
I wonder what a compression test on this engine would be. With the miles on it the thing might be misfiring on a cylinder causing the vibration I dunno and this morning maybe not a whole lot of help

 

I've put a lot of miles on cars, too, like 325,000 on a 1965 Caddy, and have found the same thing, that when a CV joint is going it will make clicking noises or some kind of noise during tight turns. My Saturn only has 108,000 on it and has fairly new tires which are rotated and balanced regularly. I don't encounter really steep hills very often, especially in this part of PA where we live, so I just go happily on my way and smile, thanking the Lord for helping me find such a good little car. :-)

 

Well, I had an idea while driving down the highwayat 70 mph....

If the vibration is coming from somewhere in the drive train, what happens if I de couple the the tranny from the engine at speed (it's a five speed)?

So i shifted it into neutral --- and-----absolutely no change.

I thought if the vibration was shaking its way back through the drive train to the engine (hence the motor mount being so badly worn), decoupling the load from the engine should somewhat isolate it from the rest of the drive train, as everything is in "free rotation (not really but you know what I mean).

I then realized that the parts in free rotation don't need to be "driven" by the tranny output to resonate.

SO the mystery continues

 

Is there an old school repair shop near you that can spin the tires on your rig? Back in the 70s we had to spin balance 240z front tires on the rig to make them smooth. Of course we didn't have computerized tire balancers back then. There is a fine tune button on most computer balancers.

 

I'm sure there is.
I also have a brother n law with some type of bubble leveling setup but I have not seen it nor have we tried it.

When I last visited the alignment shop for the Escape, I specifically asked the service writer, who used to be a tech and has been w the company many years, if the guys on the shop floor look for things like wobble caused by bent rims, out of round tires, etc. "He said they are supposed to. Otherwise, if we ignore or don't look out for these things, and an existing problem worsens, for example, the customer unloads on us--and for good reason. We're a tire and alignment shop -- if you can't leave here with balanced wheels and your car aligned, then we're not gonna be in business very long".

Gonna go do my reading

Thanks