This is precisely why I created this thread and why I look forward to responses from various viewpoints. Thanks.

 

Good luck with figuring it out. I'll ask some people for they're opinion, but I would still go for the mounts/insulators. I belive trust only paid 23 dollars for one of the lower insulators. Maybe just spend the 46 dollars and see if it improves; that would be the best way to test whether its the mounts/insulators. And if it doesn't help, then at least you won't have the cracked up, worn out old ones.

 

This may end up being my course of action, but I hope to get more input before making a decision.

 

Bump for more feedback.

 

Ron:

I believe that I have read your initial post carefully. As a method of diagnosis, can you get beneath the car on whichever one you believe the muffler to be vibrating, and see if you can verify visually that the exhaust has indeed come in contact, or very nearly met the body? If so, will gently jacking the engine up at the various points of the mounts offer more clearance? I am relatively certain that you have thought of this method, but I was curious as to the outcome.

As an aside, on earlier model Japanese cars that I have been exposed to with significant vibration while in gear, the replacement of motor mounts have always fixed the annoying problem of “idles fine in park and vibrates in drive”. If it were me, I would start with just the ruptured mount, and then one insulator/isolator at a time on the worst vehicle. This methodical approach may offer you insight as to which areas are more prone for wear.

Just a couple of thoughts, good luck and I am certain that you will post the findings as you proceed.

All the best,

Ed Fisher
Dallas, Tx

 

Ed, thanks for the feedback. In particular, your comment above reassures me that I am on the right track.

 

Is this while you're stopped? Assuming this is happening while you're stopped, shifting gears, using the brakes all requires engine vacuum and since the motor is idling there is minimal vacuum so it draws power from the motor causing a lower idle, which combined with your bad motor mounts will cause excess vibration.

 

Yes, the vibration problem occurs primarily when idling at a stop. I'll hook up my scan tool to measure the drop in idle speed under these conditions but, based on the dash tachometer, the reduction in idle speed is not excessive. I likewise attribute the enhanced vibration caused by running the A/C to increased engine load.

All responses so far point me to replace the motor mounts/insulators, but does anyone think that replacement of all of them will be necessary to eliminate the excess vibration?

 

Ｉ　ｗｏｕｌｄ　ｒｅｐｌａｃｅ　ｔｈｅｍ　ｊｕｓｔ　ｔｏ　ｒｅｐｌａｃｅ　ｔｈｅｍ　Ｂｕｔ　ｙｏｕ　 ｃｏｕｌｄ　ｐｒｏｌｌｙ　ｇｅｔ　(stupid windows IME was on..) but you could prolly get away with just replacing the one directly in the rear with an after market mount.

 

Are you saying that the rear mount is most important for reducing vibration produced by the engine?