If it's a cambelt-related issue, your engine may start to act up once it reaches 2,000 to 4,000 RPM. You might also hear odd noises when you start your car, and smoke might come out of your exhaust as well. You'll know the damage to your cambelt is extensive if your vehicle suddenly stalls in the middle of driving. These are just some of the common signs that you should get your cambelt replaced as soon as possible.