06 pt cruiser If I have bad motor mounts will it cause vibrations from 52-65 mph? I had the tires rotated and the balance checked they said they were good.

Turn off the a/c & see if it still does it
Try dragging the brake while still on the gas to turn off
torque converter lock-up & see if changes
Check front drive axle CV Joints.
Check motor & trans axle mounts

Most likely a tire/wheel balance issue. The weights that are used to balance the tires can sometimes fall off. Generally how far out of balance it is determines when and how bad it will shake. Unfortunately this is not fixable without a tire balancing machine, has to got to a tire shop.

Were the tires rotated or replaced recently? Most major tire shops will check the balance for you at little or no charge if you take it back to the shop where the work was done.

You can also try to identify the problem tire by rotating the front and rear tires one side at a time. For example, if the vibration is coming from the front, swap the front and rear passenger side tires and drive the vehicle again. If the vibration moves to the back it's most likely the (now) passenger side rear tire that's out of balance. If the is no change, try the driver's side tires.

Hope this helps!

A vibration such as you are talking about could be caused by more then one thing. First it could be caused by a broken belt in one of your tires. I could also be caused by a bent rim, a warped rotter, or a bad cv joint. I hope this helps you solve your problem.

IF your front end is jacked and your front tires are spinning you should be able to see the vibrations. Use a stethoscope on your motor and tranny to isolate vibrations while running.

In your case id start with wheel balancing first. Have them balanced on the car too (ofcourse). Having it only at a specific speed indicates its a harmonic vibration (vibrations that only occur when something rotating,reaches given speeds)
So yeah, start with cheapest repairs and go from there.

I highly doubt its your mounts unless they arn't sitting or torqued properly. If your confident they were installed perfectly i'd ignore that possibility.

Also, with front end jacked and car not running wiggle your wheels left/right, and up/down to see if any play. Spin them and look at them from the front to see if they wobble.

other causes are, tire with a bad tread, one thats about to separate, this is what caused my car to vibrate
deeper causes can include a bad flywheel,, broken or bad motor mount, and a simple alignment

Have the hubs inspected and the tires balanced. The wheel/tire assembly out of balance will cause the over 60 mph wobble/ steering wheel shake or drone. When did this occur or has it been going on for a while now?

Check out the following site:

http://townhall-talk.edmunds.com/direct/view/.f0db846

You could have a bad drivers side axle shaft. I assume that the wheels have been balanced. Good luck!

it could, but only if the new mounts were misaligned when they were installed. did the vibration begin right after installing the new mounts?

From my experience with vibrations. First does it vibrate while not moving but reving. If it vibrates with or without moving it could possibly be a broken motor mount check your motor mounts to be sure they are not broken. If it only does it while moving it just may be one of your tires with a bad spot. If you keep riding on it you will find that problem shortly ( it will blow out and have a flat tire). Also if its while moving it may be a balancer on the cv joint. If its neither one of those check for any kind of balancer as in a pulley balancer or anything on a rotating part.

i have a pt. and i have never had to change the mounts so if it doesn't vibrate don't worry about it see ya!

This may be caused by bad motor mounts. Lift your hood and then start the engine. Put it in reverse and hold the brake. Push on the gas peddle and watch the engine. If it trys to roll over they may be bad. Be careful.