I have a 2007 mazda 3 2.3l hatch.I am learning the difference between the failed motormounts. mount number 3 has the fluid in it i believe and is the one that is known to fail "passenger mount".But i think my problem comes from the number 4 or "rear mount".I have read that it has air holes.no clue what that means.but i get wheel hop and lots of vibration at 60mph.So i dont know which one to replace?????? am hoping someone can lead me in the right direction to buy these two mounts? I saw virgin talking about a 70 something or the other that dampened a lil and had no air holes. i dunno....i dont think my problem is the #3 mount,but i could be wrong.Most of the shaking is on the passenger side.i will gladly trade idle noise for a smooth 60mph ride if anyone can help

 

The rear monts on the mazdas don't have breakage issues. I'm not sure who said something about "air holes" but I'm guessing they have a toolbox full of duck tape and pliers. The rear mount issues are noise issues only and that's from gravel getting in the backing and when u accelerate or in an automatic shift from park there is a clunk noise. The #3 motor mount which is oil filled and is on the passenger side of the car are junk. They last about 2 years tops. When they leak out all the oil and are not changed they wear all the rubber down and there is about an inch and a half play in them. This with cause an array of problems due to the motor moving and throwing off balance. Replace the mount if it has leaked out the fluid. I would not worry about the two other mounts.