I have an 01 infiniti i30 (i know i should've posted in the infiniti section but this one seems to have more responses). I'm pretty sure i need a new motor mount, just not sure which one. Symptoms are a slight growling sound on light-moderate acceleration, however when accelerating full throttle it is quiet. would this be a front/rear or side motor/trans mount.

 

Check eBay for buys where you can change all.

Most times the mount next to the coolant, then tranny by driver side, then engine/tranny by radiator, then last by firewall goes in that fashion.

I paid under 300 for all 4 off eBay (then) and did the surgery in my Garage.

Let us know what you find out

 

Well i checked all the mounts and they all seem fine, no rubber tearing or hydraulic fluid leaking out of them. What else could it be?

 

Doesn't sound like a motor mount. A motor mount will usually "clunk" when getting on and off the gas. There's not really enough to make a diagnosis here yet.

This is the place to ask Infiniti questions. Especially mechanical questions as they're the same car underneath.

 

Not saying you're wrong, however in my past history of vehicles i remember clearly i had 3 vehicles with exactly the same symptoms and noises and a motor mount was the culprit, that's why i immediately figured it to be the same in this case.
Also in further diagnosing in the test drive i found that the noise always happens under heavy engine braking, for example if i put it into 1 and accelerate to nearly redline and then let off the gas. Also, it might be related and seemed to start around the same time as this issue i have a clunk in the front passenger side suspension area after i go over speed bumps, not when i go over the bump but right after when the wheels start to go back down after the bump. Im thinking of changing out the mount on that side and see if it helps, could it be possible that the mount looks ok but is still worn out somehow?

 

It's possible for the mounts to be bad and look alright.
There are two large mounts on the cradle under the engine. The rear will tend to fail due to oil leaks or just time.
The single mount on the top passenger side (over the belts) can also fail.

Have someone get on the brakes and rev it while in gear. You'll be able to see the motor move a good bit if a mount is bad.

If a lower mount is bad you'd be better off unplugging them both now and replacing the electric mount with a solid one. The powered mounts can back spike the ECU and kill it.