What are signs of bad motor mounts.

[MS6ACY]

Hey guys i have a 06 ms6 with about 32k on it how do I know if my motor mounts are bad. Because when is shift i hear a nosie like a knock and also when I start the car.

 

[batou079]

sluggish response (i.e. lose of some hp to drivetrain & engine movement), engine has more movement and could be the culprit of the knocking noises.
dont forget to check the rear diff, that knock @ shift is somethings due to rear diff mounts breaking.
Physically it will be obvious if they broken, the rubber will have big tears in the mounts. If they are really bad off, there will be small amount of liquid dribbling off of them.

 

[MS6ACY]

ok thanks man

 

[thewheelman]

I'm willing to bet that it is your passenger side motor mount. I'd been dealing with this for a while, and after replacing that mount with the AWR engine mount, the problem has gone away. If you want to check the mount, put a jack under the oil pan, and remove the top of the motor mount (2 bolts on the timing cover, and one on the liquid filled mount. If you can easily wiggle the the aluminum post in the center of the mount, it's bad. You can find a replacement stock mount online, or get the stiffer aftermarket version (which does transmit more noise to the passenger cabin, especially at high RPM).