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Slight vibration problem from about 68 up

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I'm new here, and wondering if anyone could shed a little light on my problem. I just recently purchased a 2001 STS with 41k on it. I experienced a shaking through the steering wheel and my seat when getting up to 70mph. I took the car to my local dealer, and they told my all the wheels needed balancing. So I said fine, do it. They told me they test drove it, and now the car was fine. I took it out on the freeway that night, and it was even worse than when I gave it to them. I mean really shaking at 60. I took the car back that night and left it there, leaving a voice mail for the service manager. The next day they called and told my wife, I had a defective tire, and a out of round wheel. I was to pick up the car with a new tire on it, and the wheel was ordered. They told her it would take a week or two. I didn't drive the car because I have other vehicles, and didn't want to until the new wheel was on. Today, it was only a week, but I figured, why so long, the wheel should be coming from only one state away by truck, why so long? So I called the dealer, and guess what, it must have just arrived. So I ran down, had them put the new wheel on, and asked if it was test driven, and of course they said yes, it's fine now. I jumped on the freeway, ran up to 70, and got the vibration again. A little softer now, but still there. Am I asking too much? I don't think so, I just got rid of a '92 RoadMaster with 138k on it, and it always felt the same from 10 to 85mph. I realize my STS is supposed to have stiffer ride than my old living room on wheels, but is this vibration normal, or is my dealer missing something? Any input as to the cause wold be appreciated. Jim

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Welcome to the forum! JohnnyG here, the biggest advocate you'll ever find for "Road Force Balancing" particularly on the GSP 9700 tire machine made by Hunter.

Do a quick search for any or all of the words above and read. Most of the things you read will have been written by me. Not that I'm particularly proud of that fact, but I still wonder why the dealerships have not caught on to the balance problem you are describing. It occurred to me lately that if you have an extended warranty that the latest game in town for them is insurance fraud. A new wheel is probably the last thing you need, but whatever.

As you are reading, keep in mind that it's NOT the machine that does all the work, it depends a lot on how you interact with the guys doing the work. Last time in, I took a small bag of McDonalds cheesburgers in to hand out, it helped a lot.

You must get the tires below 14 lbs road force, or you will feel them. The problem is worse when coasting down from 78 to 68, and for some reason, right at 68 is the worst. Match ALL the tires to the rims, not just the ones the machine rejects (24 lbs). Don't go about this with cold tires, don't pull a car from a parking lot after sitting all night and expect to have a round tire.

Sorry to be so short, I just finished watching the last episode of 24 and was hoping for about 12 more.

Never underestimate the amount of a persons greed.

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Welcome to the world of Cadillac's. If you search the history of these posts you will find lots of info about the vibration that these cars make from 65 MPH to 75 MPH... The most common speed is 68 MPH... The jury is out as to why these cars do this... And the level of service you will get will vary DRAMATICALLY from one dealer to another...

Let me précis all of the suggestions into one post.

Here is what you should try:

1 ) Are you running OE Goodyears? They aren’t the best tire in the world…When they wear-out, replace them with a set of Michelin’s

2) Seek out a firm/dealer in your area with a Hunter 9700 “road force” Balancer… Pay the extra to have your tires “road forced”… Most report this works (not all though)

3) There are a couple of TSB’s on this problem.. GM will try and replace the lower control arms… Some report this works (not many though)

4) Some dealers will blame the rotors… A couple have reported that turned rotors have solved this too…

5) Some have pointed the finger at the motor mounts… These are “easy” to fix… If they are shot it means the car has been driven hard (not a bad thing) or has been in an accident (not a good thing)… Bad motor mounts shake really really bad

6) I’ve seen one or two posts blaming a wobbly torque converter. Given the mass and “speed” of a torque converter IMO you would feel a wobbly one from the ground shaking a block away…

Good Luck

PS my personal opinion about the vibration is that these cars are so smooth at most speeds that you notice a vibration that you would have ignored in any other car… Oh and if it helps my neighbors BMW 540 shakes at 72 MPH


Easin' down the highway in a new Cadillac,

I had a fine fox in front, I had three more in the back

ZZTOP, I'm Bad I'm Nationwide


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Since I purchased my '94 STS, about 7 years ago, it always had a bit of a shake above 65 mph. Many balances and wheel/tire investigations, however no absolute fix.

I recently installed new tires and had the "full treatment" road force Hunter 9700 balance.

It now is absolutely smooth at any speed.

I would have bet money that the Hunter would not have been able to provide that kind of balance.

It's well worth the money.


2008 STS V8
2016 Colorado Z71
1970 Corvette LT-1 Coupe

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I know of the Johnny G posts.....very helpful info....

He is correct...if the tire force goes much beyond about 12 pounds....you will feel it on a Cadillac.

Tires are distributed on a tier system....

The GM plant gets the best ones...

The brand store get the seconds...

Then down the food chain....

Internet tires...

What you really need are GM screened tires. A cadillac dealer selling the GM part # Michilin vs a GM dealer selling Michilin tires.

Tire manufacturing is a very extremely complex process. The process is all over the place. You cannot tell by loking at the tire. Go for the best ones. Pay the extra money for screened tires.

Install procedures.....A 'tech' can very easily damage the tire during installing. Overstretch a side wall and you will never see the damage. The tire will look perfect. It may balance ok....but you will still feel it....

IMO is....the Hunter unit works great on a good tire. It cannot fix a bad tire

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Thanks for the info guys. My wife spoke with the service manager this morning, and he insisted the car was fixed. So, she will stop in and have him drive it with her in it. If nothing comes of this, and I have a feeling it won't, I will look for a place with the above mentioned tire balancer,along with a different Caddy dealer for servicing. And, when I do replace the tires, I will get Michilins. I hope my experience with this car gets better. I did reserch for a couple months what car I wanted to buy, and even what color, and amount of miles that would be acceptable for the year I finally purchased. I drove two hours from my house to look at this car and passed on a lot of closer ones because of the exterior, and interior color. I had to have Graphite with a Black interior.

sts4.jpg Otherwise I really like the car, it has the luxury like my RoadMaster had, and accelerates a lot quicker. Although, not as quick as my other car it shares the garage with, a '71 Buick GS 455 Stage 1. At least the Caddy gets over double the milage though.drag.jpg Thanks again. Jim

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Welcome Graphite-sts, I had the exact same problem with my '01 STS when I bought it.

The first thing I did was to get rid of the Goodyears and replaced them with BFGoodrich's Traction T/As'

I haven't had that problem since and I have had my car up to 90mph every so often. Besides they look great.

Peace B)

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This sounds all too familiar. Mine is a Crimson Pearl 2001 STS with 4x,000 that has a shake at 65, worsens thru 68, and diminishes again at 70- on new tires.

A road force balance found a defective tire, and that was replaced under its warranty, and I had the rotors turned, pads scuffed, new tire balanced, etc- STILL SHAKES.

I wonder if things could have gone awry when GM reset the toe. My steering wheel was replaced under warranty, and the new one was at a nasty angle from center while you were driving straight. So their fix was to reset the toe. Any thoughts on this? The shake started soon after this. Would another alignment show this?

Incidentily, this same large CADILLAC dealership has returned the car to me twice after an oil change with the oil light flashing, and the level 3-4 quarts low. Hmmm. Once was on me, the second was a complimentary "we're sorry" for the first time. Also, they didn't adjust the shifter cable after working on the console, and returned the car to me with the gear selections one off all the way back. The windshield was replaced under warranty and they failed to reconnect the radio antenna- which they claimed was built into the rear glass of the car. (I fixed that one myself, sometimes its pointless to prove a point). How can such large dealerships with large, busy, service departments provide such shotty service?

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I don't know, but rather than settling for it, maybe lodging a complaint would help with the General Manager.... He wants future sales and if he thinks his service is going to prevent that I am sure your complaints will be heard. Sometimes going OVER services heads with clear cut issues will make them realize they have a bone headed service manager who doesn't give a SHI*. Those problems you have experienced with service are unexcusable and they give Cadillac a bad name.

I believe that service should be better than it is, I was just talking to someone about it today.

I ordered oil filter adapter seals and they sent me seals for a 4.9 that look nothing like the ones I took out, I mean this is their JOB! And its not like they don't make over 100% profit on the parts. :blink: I don't know what the answer is but they better cure it or get rid of the dead wood

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