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Need to replace front motor mount?


Chris

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Good afternoon,

One thing that's bothered me since I got this car is a mild-moderate "clunk" when engaging/disengaging Drive.

It isn't excessively bad, but enough to stop my habit of shifting into Neutral at red lights.

I've read that with no 'dogbone' motor mounts, this is a common problem on the 98+ Sevilles.

  1. I understand that there is 1 front motor mount (and 2 rear?)? Where are they located (everything is hidden with plastic cladding and I can't find an diagram on Google)
  2. In this video, I start the car, then shift from P-R-N-D-N-R-P, with a pause each time before changing shifter position. I do not brake torque at all, though the engine is revving higher than usual due the the engine being cold. Does this appear to be excessive movement?
  3. I read that "by the book", changing the front mount is a 4.3 hour job. Does this sound about right? No one will give quotes over the phone, so I plan to take the car in sometime this week but would like a rough idea.

Thanks for your help!

Edited by Chris

-Chris

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Remove the lower splash shield and you can see the front mount. Without the torque struts it takes a lot of stress at WOT. I fabricated a set to remove all the stress from the front mount.

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Thanks Ranger, I will take a look next time I'm at my parent's home (no access to garage or tools where I live!)

Are you able to comment on the amount of engine movement in the video (and if it suggests a worn mount?)

Thanks again,

Edited by Chris

-Chris

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Chris, I had a bad mount on my 96 but I had dog bones and the engine did not move a lot. But I had graininess and vibration at highway speed and during braking. I believe your year has a very different front mount, they are oil filled look for oil and cracked rubber, get your hand in there and feel around, mine had a big crack.. but it could only separate so far

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I wasn't able to watch the video, but there shouldn't be too much movement with a good mount, but without torque struts there will be some. Mine doesn't move at all with the fabricated torque struts.

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did all 5 of mine on my 96 Deville last year. the passenger side trans mount and the dogbones were shot. The dogbones make alot of noise when the bushings go bad

GM FAN FOREVER

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  • 3 months later...

Hi guys,

I took the car to a dealership and had the front motor mount replaced in late July.

I'm still having the same problem with clunking between R-N-D. With the hood open, the engine noticably rocks switching between gears.

The side mounts look good, and I had my dad video tape the front mount while I changed gears:

. I'm not sure if this is excessive movement - it is quite bad shifting into both drive and reverse (my dad has "reverse" and "drive" backwards in his narration!) Could the replacement Delco mount be bad?

Any other suggestions?

Thanks!

Edited by Chris

-Chris

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The mount is oil filled. Pull the lower splash shield and you can get a peek at it. If it has failed, the rubber will be ripped and the oil will have leaked out.

Hi Ranger,

I did pull the cover, and the video I posted on youtube (please see my last posting and not the original post) shows the front motor mount as I change R-N-D. The mount looks good, and there is no sign of fluid leakage.

Which stumps me as to why my motor rocks so much!

Here are a couple photos of the motor mount: CIMG8798.jpg and CIMG8800.jpg

Any other ideas?

Thanks again

-Chris

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The mount is oil filled. Pull the lower splash shield and you can get a peek at it. If it has failed, the rubber will be ripped and the oil will have leaked out.

Hi Ranger,

I did pull the cover, and the video I posted on youtube (please see my last posting and not the original post) shows the front motor mount as I change R-N-D. The mount looks good, and there is no sign of fluid leakage.

Which stumps me as to why my motor rocks so much!

Here are a couple photos of the motor mount: CIMG8798.jpg and CIMG8800.jpg

Any other ideas?

Thanks again

I would suspect it's a front end bushing. Not familiar with your model, - but on a dreadful Honda I had there is a bar that attaches to the wheel hub area and is mounted to the frame diagonally. - this keeps the entire wheel assembly secure & limits play. when these bushings wear out, it allows the wheel assembly to move when under stress (ie when the car is put in gear).

Have someone put the emergency brake on, foot on the brake, and go near the wheel and listen to the front wheel when someone shifts to drive. (you may even see the wheel wiggle a bit as the noise is made).

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Any other ideas?

There are 3 other engine/transaxle mounts, and one or more may have been damaged before the front mount was replaced - How far was it driven while broken?

___________________________________________________

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Hi guys,

I took the car to a dealership and had the front motor mount replaced in late July.

I'm still having the same problem with clunking between R-N-D. With the hood open, the engine noticably rocks switching between gears.

The side mounts look good, and I had my dad video tape the front mount while I changed gears:

. I'm not sure if this is excessive movement - it is quite bad shifting into both drive and reverse (my dad has "reverse" and "drive" backwards in his narration!) Could the replacement Delco mount be bad?

Any other suggestions?

Thanks!

The first video you posted looks like a bad motor mount. The second video of the motor mount does not look like too much movement. If your engine still has the same amount of movement as your first video I would suspect another bad motor mount, not the one that has already been replaced. Check the rear mount.

OldFart

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Hi guys, thanks for the responses:

winterset - I had the car jacked up when making the latest video and didn't notice any wheel movement at all. When you say front end bushing, are you referring to the knuckle?

KevinW - The two side mounts look to be in good condition. I hadn't realized that there was a 4th (solid) mount at the rear. I will have to take a look at that.

OldFArt - There is about the same amount of "clunk" as before the mount was changed. The view of just the motor mount makes the movement less obvious. The car's been driven quite a while like this.... 10,000km by me, plus who-knows how many by the previous owner. I know this can cause major transmission damage so am trying to have this looked after asap!

edit - Do you guys know if/how I will be able to see the rear mount?

Edited by Chris

-Chris

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edit - Do you guys know if/how I will be able to see the rear mount?

The rear mount is pretty easy to see with the car up in the air, jack stands will work. The rear mount is in relatively the same position as the front mount, only on the right hand side of the engine (near the firewall).

FWIW, the engine mounts on the cradle, and the cradle is mounted to the frame/body. There are 6 attachment points for the cradle, three on each side, and are pretty obvious to see from underneath the car. If you have not already, confirm those bolts are tight as well. I doubt they are the cause of the engine movement, most likely the rear motor mount.

OldFart

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If you put the car in a forward gear and power brake it slightly and the engine doesn't move much, which I feel it is not in the video, try reverse and it will torque the other mount. Forward should move the front mount and reverse should move the rear. If the mounts are bad a helper should be able to see the movement easily while you torque the car.

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  • 2 months later...

If you put the car in a forward gear and power brake it slightly and the engine doesn't move much, which I feel it is not in the video, try reverse and it will torque the other mount. Forward should move the front mount and reverse should move the rear. If the mounts are bad a helper should be able to see the movement easily while you torque the car.

I did this -

- There is quite a bit of movement when brake torquing in drive. On the youtube page, I have the approximate times of each gear shift (P-R-D-P).

I had the car at a small garage just after Christmas and was told all the motor mounts are fine.

The clunking seems to be getting worse when I shift (clunks at P, R, N, and D... it also occurs during driving when I go hard into the gas after coasting).

Any suggestions?

-Chris

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I did this -

- There is quite a bit of movement when brake torquing in drive. On the youtube page, I have the approximate times of each gear shift (P-R-D-P).

I had the car at a small garage just after Christmas and was told all the motor mounts are fine.

The clunking seems to be getting worse when I shift (clunks at P, R, N, and D... it also occurs during driving when I go hard into the gas after coasting).

Any suggestions?

I watched the current video and the video preceeding it as well as looking at the photos. In your current video there is a considerable amount of upward movement near the radiator which would lead you to believe the front mount is bad. The front mount itself looks good, however in looking at the second video of the mount itself it looks like a fair amount of movement between the top of the mount and the braket it bolts to. With this in mind I would focus my attention on the mounting bolt/nut. If that is tight is there unneccesary clearance between the mount and the bracket, in other words do you need to install a washer before tightening it? If that is infact secure......

The next step would be to check the cradles mounts as mentioned earlier in this thread.

OldFart

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