Motor mount fails almost immediately

Hi all. My 2009 Pontiac Vibe GT (193k, Toyota 2.4l engine) has a strange, annoying problem. It has an intense vibration at idle, but it is there in gear, neutral, and park. It is present specifically between about 800 and 1100 RPM and is smooth above and below that range. Replacing the top passenger side torque mount completely fixes the problem-for a few minutes, then the mount gives out. The other three mounts have been replaced (unnecessarily) and are in perfect condition. The last mechanic I saw, said the engine is misaligned by two degrees and just enough to stretch the mount and cause it to fail.
I had the engine rebuilt over this past winter and didn’t have this problem before that. I did have vibration at idle due to all the mounts being old, but it would smooth out in neutral or park as expected.
If an engine misalignment is causing this, it would be insanely expensive to fix and may not even be possible.
Since I’ve ruled out the mounts being the problem, I’m just wondering what else could be causing this. I sincerely hope it’s something fixable.
I suppose a lot can go wrong during the rebuilding process and it’s been suggested that the balance shafts are causing the vibration, but I doubt that would cause that one mount to fail within minutes.
The mount does look a little crooked or angled.
Any ideas would be greatly appreciated because the vibration is annoying enough that I avoid stopping if possible.

I don’t think you should rule them out… because this;

When the engine was re-installed it is likely the mechanic 1) Pried on something and bent it to get the engine to drop in, or 2) Somehow reinstalled the mounts incorrectly or 3) Let the clearances in the bolt holes all stack up to the point where that very last torque mount is over-stressed and grounded out causing it to fail and your vibration.

I’d suggest having the mechanic that said it was 2 degrees misaligned consider loosening all the mounts and their brackets while the engine is supported from above to allow correction of that 2 degrees. The engine should not come back out, just be loosened and adjusted. Anything bent should be apparent doing that. Bend it back and tighten everything back up.


That’s what my mechanic suggested too, but I can’t afford it-especially after all this unnecessary work. Then again, he’s the one who suggested replacing all the mounts and, since that didn’t fix anything, maybe I can work something out with him. I feel like he owes me that since I paid him $322 and bought the mounts due to a bad diagnosis.

I would give the mechanic one more try to make it right at no charge.
Otherwise find a better mechanic to fix it, then present the bill to the first mechanic and negotiate with him to pay at least part of that bill.
Let him know that plan C involves small claims court


Can you physically see what is wrong with the failed mount?

The thought comes to mind of an engine vibration along with whether or not the vehicle has been in a bad wreck.

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There is a bulge in the rubber underneath. The end of that rubber cylinder is concave before installation and when the weight of the engine is let down on it, the rubber bulges out. I’m not 100% sure it’s not supposed to do that. Interestingly, the bulge is different and not as much this time. I thought maybe since the other mounts were replaced after the failed mount was installed, maybe a (fourth) new one would hold up this time, but I thought better of that plan since I’m not sure it would work.

maybe they installed the wrong part numbered mounts. sometimes parts can look the same but be enough of a difference to cause a problem. or the part could of been stamped wrong. the correct part number but the wrong part.

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I ordered all the mounts from a Toyota dealer. All three top mounts matched each other and were correct. I was also assured they wouldn’t fit if they were the wrong kind. Strangely, this last one is holding up the best, but is still somewhat crushed.

I’m aware that a Pontiac Vibe and Toyota Matrix (?) were basically the same car.

However, personally I’d want to get parts for a Pontiac from a GM dealer. They could be the exact same part…but maybe not.

That could be your problem.

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Is this the one in question? If so and if ALL mounting bolts go in without a wrestling match or distortion of the mount then I wonder about whether or not the chassis is tweaked in some way from an accident.


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It goes on the top passenger side of the engine. This is the only one I’ve replaced myself. It lined up and went in easily. The other three people who worked on my car didn’t mention having to force the mounts in.

I just thought of something. The engine was replaced after the rebuild using the original mounts-all of which were shot. Then, the mounts were replaced periodically-not all at the same time-over the course of about 6 months. Could driving the car with the engine sitting on bad mounts, then some good and some bad have caused the misalignment?

Yes… but now that all have been replaced, the misalignment should be gone.

Maybe it is. He did replace problem mount before the other ones.

As an experiment, I uninstalled and reinstalled the mount in question to see if I could line it up any better. It looked straight at first, but after running the engine for a couple minutes, it tilted slightly back to where it was before. Kind of hard to see, but the gray part is not quite parallel with the black part. The right side of the gray part is further away from the black part if that makes sense.