Hey Guys,

I'm new and have no clue where to start. I have a 2000 Bonneville SLE. Awesome car. However, I have noticed that there has been a shuttering of the engine. It still runs, its still fast, but it feels weird. I went to a local shop and had it checked out. The consensus came back as a broken engine mount. He said it was from accelerating too fast. He says that this will be expensive to fix over a Grand. Is this possibly a problem with the car itself, perhaps something that should be covered by a warantee? I wouldn't think that an engine mount should just break from accelerating. I know this is a powerful engine, but shouldn't mounts be made to handle this power???

Any insight would be great. Also if anyone could point me out to where I could possibly get parts and labor done at a good price in the NJ area, let me know. Thanks guys.

Haven't heard of any problems with engine mounts failing. Are they referring to engine mount, or the mount bracket itself? The price estimate for replacement sounds high either way.

Have someone rev the engine while you look at it, from the side and the car in park.
Does the flex seem excessive?
There are a few that have replaced the front mount with a solid one, I have the mount too but have not installed it yet.

I had a bad plug wire this spring and it felt like the engine mount had let go too?

This is a possibility. Do as Pdad says and open the hood and simply rev the engine in neutral using the throttle body linkage yourself. You will see how much the engine moves. Observe the front engine mount.
It is an oil filled damper. It is quite expensive and will cost about $500. to replace.

Pdad - I'm surprised that you haven't changed yours out yet. It will definitely extend the life of your exhaust headers flex joint and intake pipe/shroud.

My solid mount is still working perfectly and the extra vibration is not really noticeable.....and my wife doesn't complain, so that is the true test.

I am doing the mount at the same time as the cat removal, no time lately it seems.
I need a weekend off so I can take care of a few loose ends :P

Would you be able to place transmission in Drive, then rev engine very lightly while holding brakes to stop forward momentum. This would place some loading on the engine. Or not a good idea?

I wouldnt temp it but also dont think its necessary. With the engine in park and a little lite reving the engine will twist enough to see the effect.

That'* right. No need to put it in drive. You can do it yourself and it will be much safer.
When I rev mine with the solid mount, in neutral, I can see the whole subframe flex slightly. Before the solid mount the engine moved a couple of inches. Very visible in neutral.

I am the inventor of the solid mount for the 2000 Bonneville. To check the front motor mount put the car in park, open the hood, with engine off, rock the car backwards, look down at the motor mount and see how much it flexes. The motor mount is about four inches in diameter and about three and a half inches high. When you excellerate that motor mount tries to rip itself in half. I have over 20,000 miles with my new solid mount and I have no complaints.
Rod

Thanks for your great invention Rod. Works like a charm.

If I could only make one modification in the design, it would be to install another urethane donut underneath between the bolt head and subframe to cushion it when in tension. The urethane cushions on top, as designed, only cushion in compression, so in forward motion it'* metal to metal contact. Only a very slight noticeable vibration that causes the rearview mirror to distort a little but not enough to be annoying.
It would be simple to modify with a longer bolt with washer and custom urethane bumper that would fit the recessed hole under the subframe crossmember.