I was told that the motor mounts on my 2003 MCS may start leaking (has 35,000 miles on odometer). After reading the forum postings it appears that it only applies to 2004 and newer. Regardless, the repair facility felt that the large two piece upper motor mount could benefit from new bushings, so - I bought poly bushings and installed them (took about 10 minutes) and went for a ride. In motion no problem, but at stop with the motor running I felt a noticable vibration, and when taking off slowly I could hear a vibration rattle that wasn't there before. Went home, took out the poly bushings - vibrations disappeared!!!

I should have know from my hot rodding experiences with small block Chevys that poly bushings are very rigid and don't have any play, and often lead to squeaks and harsh rides.

Just wanted you to know my experience so that you don't waste your time and money and end up unsatisfied as I did.

 

All poly bushings will transfer more vibration, noise, ets. than stock ones. They are made to improve performance by reducing movement, and slop. Your shop should have warned you about this.

Sorry you got them for the wrong reason. They aren't cheap.

Motor on

 

I ended up using just the Powerflex inserts for the large end of the upper and lower
motor mounts. And then I took one of the top large inserts out because
of increased vibration with the a/c on at idle. Also, I found that if the
steering wheel is all the way at the top of the adjustment range, it vibrates
the wheel too much and backing down a smidge quiets it down.
I'm happy with the end result running 3 inserts and skipping the small
poly bushings and the trans mount inserts.

 

mount inserts will also give you vibrations, especially if you only install one mount. some people actually like the feel. makes it feel more race worthy.

 

Where can you get just the inserts? I've seen the bushings and mounts in Moss, but isn't that the whole mount or is it just the insert? I'd like just the insert because I just installed my engine damper and don't wanna remove it to replace an entire mount.

 

In MossMini, you can order seperately, the lower small bushings the lower
large bushing inserts, the upper small bushings, the upper large bushing
insert, and the transmission bushing insert.
I did the pair of lower large bushing inserts (took about a half an hour
after putting it up on ramps ... need to remove 4 bolts attaching the
mount brace to the oil pan to do it), and the pair of upper large bushing
inserts (takes about 10 minutes - later I removed one of the two
inserts to reduce vibration at idle with the a/c on).
The small bushings requires the same effort plus pressing the old ones
out and the new ones in. A bit of a bother, but doesn't need a press like
the control arm bushings need - I didn't do it as I thought it would add more
vibration than it would remove engine movement.