Shaking car syndrome


#1

My niece has a 2005 Chevy Malibu (LS I believe) with a six cylinder engine. It has approximately 108,000 miles on it. It has new tires, a recent oil change, and a new battery. Generally, it rides very smoothly; however, occasionally, when she drives it for a number of miles, it will start to shake when she reaches 30+ miles per hour. She has taken it to a local mechanic, who drove it on a longer test drive, and the mechanic cannot replicate the issue. The check engine light is not on.

Does anyone have any experience with the cause of and solution to this problem?

Thanks


#2

Can you describe the shake? Can you feel it in the steering wheel? Does it matter whether or not she is accelerating? Is the frequency related to the wheel speed?


#3

Simplest test: rotate the tires. If shake goes away or lessens greatly, you’ve got unbalanced tire(s) that are now on the rear.


#4

…also check tires carefully for bulges on the tread areas, a steel band could have ruptured. ask if she hit a curb or speed bump recently. if convenient drive with spare on the most suspected wheel or wheels and see if it goes away


#5

If shaking is worse under acceleration but disappears or lessens as soon as you let off the gas, a bad front axle/CV joint is also possible.


#6

Thank you all for your posts. I will explore your questions with her further. I do not believe that it is anything related to the tires because it does not always happen. For instance, she can start it cold and get on the interstate and travel at highway speeds without an issue. Only occasionally and after she has been traveling for a while does it happen.


#7

I had the same problem with a tire tread bulge and it did not vibrate always. it was intermittent, so I would carefully inspect the tires still.


#8

I would have to agree with Insightful on this one. There are 2 ways a tire can be out of balance. If the shaking occurs around 55 MPH it’s the tire hopping up and down. If it occurs around 35 MPH it’s the tire moving left to right and will often ease as you increase your speed and get out of the resonant range of the unbalance. Moving the front tires to the back will stop this type of unbalance because the tire/wheel is held more rigidly as opposed to the front where they pivot to allow steering. If it seems intermittent it’s because, as with many resonant situations, it can be borderline but once it starts it keeps going. If the tires are new I would suspect an improper balance job or a defective tire.