Chrysler Repair: Symptons of Worn Timing Belt, interference engines, rough sound

Question
What are the things to look for if your timing belt is going bad?
I have a rough sound to the motor, and the ride in my car is no longer smooth on interstate nor highway driving.

I have all four tires replaced -two over eight months ago, and two more last week, so the only other thing I can think of is timing belt, which is over 100,000 miles right now.

Please reply.

Answer
Hi Jeanette,
The timing belt wear is generally not going to be noticed as roughness either of the engine or the rolling of the car. It generally will just break without notice. Depending upon what engine you have this could be an inconvenience from the breakdown, or a major repair due to consequent internal engine damage. The former occurs if the engine is 'non-interference' and latter if it is 'interference' in its design. Although recommended belt changing at 100,000 miles is common, another approach, particularly for non-interference engines, is to simply inspect the belt for wear from time to time which involves usually simply removing a timing belt cover and looking at it carefully. So let me know the make, year, and size (L) of the engine in question.
On the road smoothness issue, is it vibration, or other sounds that accompany the feeling? Or is it lack of control/wandering? Or excessive bouncind following bumps? It is difficult to diagnose what the problem might be second-hand. The tires might be out-of-round, or need to be re-balanced, or what is call 'match-mounted' if out or round, to the particular wheel. You might ask the tire salesperson to drive the car and see what he thinks.
Roland