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2001 seville sls


arstaff

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Just purchased this car and have had severe vibrations starting at 57 mph....installed new goodyear eagle gt-hr tires....had dealer balance them..little better but still lot of vibration..............any ideas of cause and cure ??

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Check the front lower engine mount. Remove the lower cradle engine mount bolt. Then jack the engine up slightly. If the bolt wobbles....its a bad mount.

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Logan, why would this part cause the vibration? And why at 57 MPH? As you undoubtedly know, I blame all vibrations starting about this speed on tires and rims. You also know that I am a big proponent of road force balancing....done correctly. What, in this post, leads you to believe an engine mount is the culprit?

Don't get me wrong. I'm glad you mention that there is a possible failure mode going on that has not been previously brought up. This is particularly true of the post '98 model year. Prior to that year, the "dog bones" were mentioned a lot.

Arstaff, I suppose I need to ask where this vibration is being felt. And what is your definition of severe? Does it seem to "modulate", in other words, vary in intensity, as you drive? Does it sometimes dissapear altogether?

Never underestimate the amount of a persons greed.

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Do a search on vibration and you will find a post by me on all the issues I had with my front end including vibration. The end result was a proper wheel balance done on a Hunter GSP 9000. I think that's the name of the machine. Do not get any balancing done at your dealer. My dealer chased my vibration for 6 months which included a least two balancing. They replaced thousands of dollars in parts and I finnally convinced them to let me take it to a proper tire shop with proper equipment (with a tecnical service bulliten TSB). $120 bucks later(at the cost of the dealer) vibration gone.

Do not waste the time I did or any money untill you get a proper road force balance done on a Hunter.

Hope this helps

2001 STS Mettalic Otter Grey, Black Leather, 213,000 kilometers - miles - ? Still running strong!

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The later cars do not use the upper dogbones. They are riding on just the lower mounts.

My 2001 Deville had some vibration 65-71 mph. Just by chance the car was updated to a DTS....so different wheel and tire assemblies ended being put on the car. Same vibration.....The DTS wheels/tires were balanced on a Hunter 9700.

Finding it hard to believe that 2 completly different wheel assemblies could cause the same exact vibration.....I started checking the mounts for a driveline vibration.

Sure enough the front lower mount was torn. Pretty much fixed the vibration issue.

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My 99 has an odd vibration at 70ish but it really feels like tires or alignment.. it also 'sways' occasionally like im being hit with large gusts of wind going 80 or so .. i'm not sure if it'd wind or alignment. It's real smooth below 70 .. I visually inspected all the mounts and they look great but that could be misleading. What's the easiest way to test it?

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Check the front lower engine mount. Remove the lower cradle engine mount bolt. Then jack the engine up slightly. If the bolt wobbles....its a bad mount. Torn mount.

The old Ford Tauraus had basically the same engine mounting set up.....nightmare. Mounts would weaken/tear left and right. Vibe....vibe....vibe......

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Thanks for all your replies...............the vibration begins at 57 and is the same amount of vibration up to 75....I have not been over 75 yet..............I am going to check the mount and then try the Hunter approach....Thanks again

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Check the front lower engine mount. Remove the lower cradle engine mount bolt. Then jack the engine up slightly. If the bolt wobbles....its a bad mount. Torn mount.

This is good stuff. I'm just not following your diagnostic procedure real well. "Remove the lower cradle engine mount bolt" is this on the frame or on the engine? "If the bolt wobbles...." what bolt? I thought we just removed it.

Never underestimate the amount of a persons greed.

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The mount has the engine weight on it while its just sitting there.

The lower engine mount stud passes thru the front cradle. There is a hole in about the bottom center front of the engine craddle. This is the access hole to the lower engine mount stud.

Remove the nut from the lower engine mount stud. Jack the engine up slightly. This will take the engine weight off the mount.

Then....thru the craddle access hole....try to wiggle the lower mount stud. If it wobbles loosely....its tearing away from the lower mount.

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The mount replacement procedure is incorrect in the service manual.

No way you are going to remove the upper mount nut (under exhaust manifold) in the car.

You have to drop the front cradle....then remove the mount with the upper 'Y' bracket shown in the image. Then replace the mount on the 'Y' bracket...and reinstall the complete assembly.

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OK Thanks! It makes sense to me now. What are the chances that the lower stud might be torn loose instead of the upper? I suppose if it were, it would be readily apparent when the lower nut is removed.

I never got into my '99 that deeply yet, I was wondering what replaced the dog bones. To make matters worse I assume this part must be under tension during hard acceleration....right?

Never underestimate the amount of a persons greed.

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The upper lower mount is solid metal bowl if I remember. The mount will look ok with the weight on the engine.

You remove the lower mount nut....then jack the engine up slighty to get a air gap between the lower mount and the craddle.....it should be apparent if the lower bolt is tearing away.

Mine was bad at 75K. So there have to be a bunch of them.

I notice on another post I just did. The correct replacement procedure on a 2001 Deville is much more like the '99 STS. The 2001 Deville book has the procedure all wrong...

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  • 7 years later...

Arstaff

Just because your tires are new,don't assume they are not the problem. My nephew in Montreal put a new set of Goodyear Eagles on his Monte Carlo last fall. He immediately had a vibration problem, none with his old Eagles. The dealer rebalanced, rotated, remounted, everything but could not get rid of the vibration. Now he's claiming something is wrong with the car. Comes Nov. he has to put on his mounted snow tires. No vibration. Come sping he takes the tire dealer for a drive to show

that there in nothing wrong. Put the Eagles back on & the vibration is back. The selling Goodyear refuses to do anything else, claiming my nephew was too fussy. Now he writes Goodyear & finds another dealer who has a Hunter Roadforce who immediately pulls the 2 front & spins them and says they're defective & doesn't even check the rears because they came from the same batch. Calls Goodyear, who authorize 4 new Eagles installed N/C. No more vibration.

On the road force balancer I was told if the # comes up more than 20 the tire is no good. I don't know what the # means. My tire guy tries to get tires with 5 or less.

Norm

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I have been told by a local shop that does alignments that buying a tire at walmart is a risky proposition: I had new tires on my car that pulled to the right, much more than is acceptable, so took it to the shop. He charged me no money and said your alignment is right on. Some time later I took another car with the same problem and same result. He claims, it doesn't matter if you are buying goodyear or any other brand, the tires are made to walmart specs and that is different. I don't believe he had an axe to grind, he has done my alignments for years. He does sell tires, but did not try to sell me a tire! I personally don't buy tires there anymore, and I used to think that would be a good place to get a tire because if you had a problem with it, you could always find a store to fix, replace it. The above posts never mentioned where the tires came from, but I thought I would add that food for thought.

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Boy, those old posts from 2004 bring back a lot of memories for me. I learned a lot about road force balancing in those 7 years and will never have any other tire balancing system used on my cars. Road force balancing (and a couple of new tires) eventually fixed my '99 STS that I'm discussing in those posts. I never did get around to checking the front engine mount, but I'm certain now that it definitely had a problem. My new '08 DTS has a very different engine mounting system, and the difference in driveline control is like night and day.

Remember too that the Hunter machine is only as good as the guy using it. Many will see numbers under #15 and tell you it's good. That is NOT the case with these cars. As another poster mentioned, 5# or less is ideal, and you will definitely feel 10# or more.

Never underestimate the amount of a persons greed.

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