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Originally Posted by pentoman
Sounds nice..
is it smoother throughout the rev range?
I have a problem not with a rough idle, but instead with vibrations at ~3500 rpm and general Noise, Vibration and Harshness at high revs/high speed cruising.
Russ
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Now that I have replaced the failed mount, I realize that the car was generally "noisier" overall with the failed mount. For instance, the very next day after replacing the mount, when jumping aggressively on the throttle in order to pass a semi, I noticed a slight dieseling noise. After a few minutes of playing around and experimenting with the throttle, I realized this was actually engine pinging from the 87 octane I have been running for the last month. I had gradually been working my way down from 91 octane, all the while listening intently for pinging, which I never heard. So I settled on running 87 octane. Of course, now that the motor mount has been replaced and I can actually hear pinging, I will be working my way back up and may eventually have to start running premium again.
Also, since the mount has been replaced, I now notice peculiar squeaks and other noises from the suspension. In particular, I notice a noise somewhere in the rear which resembles a somewhat metallic squeak. It is intermittent and only seems to occur when the car shifts weight laterally, such as when cornering on a left turn and then suddenly shifting to a right turn and vice versa. I'm not quite certain what the noise is; I just had the car aligned a few weeks ago and the tech did not mention that any suspension parts were worn out or needed attention. It sounds sort of like a loose bushing, but I can't be sure. With the time off over the holidays, I will have to jack the car up and take a look to make sure everything is in order.
So it would appear that, even though my car seemed to idle and run smoothly at all times other than with the trans in D while stopped, in actuality it was running more roughly than I was able to discern.
But in specific answer to your question, although I did not necessarily experience any harmonic vibrations at ~3500 RPM, I do believe the new motor mount has smoothed the engine out considerably throughout the entire RPM range. In general, all noise, vibrations, and harshness have been greatly minimized. The car doesn't "jerk" at startup anymore (it feels kinda weird and silent now), and - unfortunately - there is noticeably less feedback in the form of noise and vibration from the engine, to the point that it seems to have transformed the car's driving dynamics from a somewhat sporty, throaty response to a muted, hushed, refined tone.
I would say it's worth a shot if your motor mounts haven't been replaced in a while. You may end up fixing problems you didn't know you had.
If you want my other unused motor mount (or anyone else for that matter) you can have it for $40 shipped. Otherwise, I will be keeping it as a spare.